Three Coins Are Tossed Simultaneously Find The Probability Of Getting Exactly One Head

In the second tossing of coins two coins were tossed 40 times simultaneously from BIO 214 at Ball State University. Number of times two heads appeared = 55. Problem 3 A fair die is rolled until each face has appeared at least once. number of steps. If the number of spots showing is six, you win $4. Let us learn more about coin toss probability formula. S7 Suppose a coin is tossed and a dice is thrown. Note: Including the words "single time" and "after" confuse this problem somewhat. Thus the probability for the spinner to land in any designated section is 1/10. e, all the cases which are possible are as follows: {HH, HT, TH, TT} where H refers to head and T refers to tail Since it is exactly one head, the cases which are favourable are HT and TH thus 2 cases out of four are favourable i. And if the number of spots showing is one, two, or three, you win nothing. (b) no heads (c) exactly one head (d) exactly two heads (e) three heads Log On. Anything that can happen but is not certain is written as a number less than one. If three coins are tossed, the probability of the event showing exactly one head on them is. Let success be that a tulip matures. Getting more Tails than Heads 5. When three coins are tossed, similarly, getting any of the side is (1/2)^3 = 1/8. They are: HHH, HHT, HTH, THH, HTT, THT, TTH, and TTT. When we toss a coin getting head or tail have equal probability of 50% - that is, out of the two possible outcomes getting the specified one becomes 1/2 probability. In tossing three coins simultaneously, find the probability of getting 1)at least one head but at most one tail 2)at least one head but at most two heads. Find the probability of getting: all heads (ii) two heads one head (iv) at least two heads === DOWNLOAD DOUBTNUT TO ASK ANY MATH QUESTION ===. Note: Including the words "single time" and "after" confuse this problem somewhat. Expected Tosses for Consecutive Heads with a Fair Coin Date: 06/29/2004 at 23:35:35 From: Adrian Subject: Coin Toss What is the expected number of times a person must toss a fair coin to get 2 consecutive heads? I'm having difficulty in finding the probabilty when the number of tosses gets bigger. Five fair coins are tossed simultaneously. A biased coin lands heads with probability 2/3. Explanation: Probability of NOT getting a tail in 3 coin toss is (1 2)3 =1 8. Note "Au B" or AB represent the occurrence of either A or B. b Posted 2 years ago. Coin 1, denoted as {eq}C_{1} {/eq}, has a probability of landing on heads with probability 3/4 and tails with probability 1/4. One is a two headed coin( having head on both faces), another is a biased coin that comes up heads 75% of the times and the third is an unbiased coin. If all the three try to solve the problem simultaneously, fine the probability that a) exactly one of them solves the problem b)exactly two of them solves c)none of them solves d) the problem is solved. Pick a milk box and a star from the shop. Q1: Three coins are tossed. Examples for Using the Classical Approach to Find the Probability. Find the probability of landing on the head side of the coin and rolling a 3 on the die. One of the three coins is chosen at random and tossed, it shows head. Probability of getting exactly 2 heads in 3 coins tossed with order not important? toss of three dice with more than 1 head. The probability of getting a head, when a coin is tossed a number of times, must remains same in each toss i. Given N number of coins, the task is to find probability of getting at least K number of heads after tossing all the N coins simultaneously. An observer not being able to identify the coins does not change that. Find probability of: (a) 3 heads (b) exactly 2 heads (c) atleast. Since the probability of getting exactly one head is 0. Now suppose that the coin is biased. COIN Four or More Coins are tossed?? You need Binomial for that. The outcomes are not the same as in part (a) because now it is possible to have one toss being from the blue-white coin and one toss from a red-blue coin, which was not a possible outcome in part (a). If the coin is fair, there is a 50-50 chance of getting a head or a tail on any toss. A person tosses two coins simultaneously and is to receive Rs. Using the above, nd the probability of each of the following events: (a) Getting exactly two heads. Find the probability of getting a number greater than 4. Three coins are tossed. So two possible outcomes in one flip. The probability of getting a head on each occasion if a coin is tossed five times is equal to 1/2 x 1/2 x 1/2 x 1/2 x 1/2 (that is, 1/25) = 1/32 or one in thirty-two. 5 and P(tail) = 0. 3, 8 Three coins are tossed once. Find an estimate of the probability that a family with three children will have exactly one girl using the following outcomes of trials of tossing a fair coin three times per trial. If the number of spots showing is either four or five, you win $1. Consider one. If the outcome of the first event has no effect on the probability of the second event, then the two events are called independent. Three unbiased coins are tossed. b Posted 2 years ago. Question: A Fair Coin Is Tossed Three Times. Manually going through the combinatorics to determine the probability of an event occuring If you're seeing this message, it means we're having trouble loading external resources on our website. Probability of getting at most one tail is 2/4 = 1/2. Users may refer the below detailed solved example with step by step calculation to learn how to find what is the probability of getting exactly 4 heads, if a coin is tossed ten times or 10 coins tossed together. c) Calculate the probability of red or green on the spinner and tail on the coin. This is out of 16 total ways to flip a coin 4 times. The following SAS DATA step simulates Alice and Bob tossing coins until they have each won 100,000 games. Let us consider the flipping of a coin. So the answer is 7/8. Solution: Total number of trials = 250. A fair coin is tossed six times. These observations are called the outcomes of the experiment. Here are the outcomes when 2 coins are tossed simultaneously where H denotes Heads and T denotes Tails. Find the probability of Getting only one head. For example, let’s suppose you wanted to know the probability of getting a 1 on a die roll. When we toss three coins, the. The probability of fewer than three, then, is the sum of the probabilities of these results, 1/16 + 4/16 + 6/16 = 11/16 = 0. After one toss of the coin, we know nothing. flip a coin and record Head or Tail, then choose a ball from an urn and record its color The branches emanating from any point on a tree diagram must have probabilities that sum to 1. Exactly one head when you toss two coins. Roll two fair dice and find the probability that the sum. Three coins are tossed. Find the probability of getting • 3 heads If 3 coins are tossed various combination possible are S = {HHH, HHT, HTH, THH, HTT, THT, TTH, TTT} n(S) = 23= 8 Let A be the event of getting 3 head A = {HHH} n(A) = 1 Probability of 3 head. 25, the probability of getting one or more heads is 0. of favorable outcomes = 2 Probability (E) = Number of favourable outcomes / Total number of outcomes. We would expect a head (H) and a tail (T) to have equal chance of occurring, i. If two coins are tossed, what is the probability that the first coin will show heads and the second coin will show tails? a. "Conditional Probability" If two fair dice are rolled, find the probability that (a) the sum is 6 given that the roll is a double (b)the numbers rolled dorm a "double" given that their sum is 11 "And" (c) If a fair coin is tossed three times, find the probability of getting heads on the first toss and tails on the second and third tosses. Probability of getting 1 when a die is thrown. enter your value ans - 5/16 Let's examine ONE case in. Example 2: Three coins are tossed at the same time. you and your partner are about to toss 2 coins 100 times. A Naive approach is to store the value of factorial in dp[] array and call it directly whenever it is required. Then S = { HHH, HHT, HTH, THH, HTT, THT, TTH, TTT } (i) Let ZE1 [ = Event of getting all heads, Then E1 = { HHH } |E1| = 1. SOLUTION: We set it up by counting how many things are in the sample space, then count how many ways of getting the three heads. If four coins are tossed, find the probability to get at least 1 head?. enter your value ans - 5/16. Use our online probability calculator to find the single and multiple event probability with the single click. Examples: When we flip a coin a very large number of times, we find that we get half heads, and half tails. Q is the event of getting either H or T and an even number. What is the probability of getting exactly 3 Heads in five consecutive flips. X is the number of trials and P(x) is the probability of success. Class 11 Maths Probability Ex 16. The objective is to find the probability that the outcome is three heads. 1 Q32 Six coins are tossed simultaneously. Toss three fair coins and find the probability of no heads. An ideal unbiased coin might not correctly model a real coin, which could be biased slightly one way or another. Thus, the probability of getting, on one trial, the result HTT must be 0. Then repeatedly toss the coin eight times in a row until one of the declared 36 strings occurs, and take the corresponding pair to be the roll of the two dice. c) Calculate the probability of red or green on the spinner and tail on the coin. These are the three possible ways that we can have exactly one head, depending on where exactly that single head appears. Q1: Three coins are tossed. 3, and Miscellaneous Extra Questions NCERT Solutions are extremely helpful while doing your homework or while preparing for the exam. Use Scenario 5-4. We can write P(head) = 1 2 or P(H) = 1 2 , both of which read ‘the probability of getting a head is one half’. Three fair coins are tossed- whats the probability of tossing at least one head? The chance for each toss is 1/2. Suppose you toss a random one of these coins. Two fair coins are tossed simultaneously. Draw the tree diagram to find the probability that both of his pizza is fresh or stale. Exactly one head. Since the probabilities of heads and tails are identical for a 50/50 coin, each of the two possibilities must have the same probability by symmetry. Let us consider the flipping of a coin. If three unbiased coins are tossed simultaneously, then the. In other words, if we were to repeatedly toss the coin many times, we would expect about about half of the tosses to be heads and and half to be tails. Three coins were tossed 30 times simultaneously. You can also learn how to find the Mean, Variance and Standard Deviation of Random Variables. Staying with the experiment of flipping a coin three times, we could look at the event of getting exactly two tails. Definitions An event is a collection of one or more outcomes that share a property of interest. In this scheme you repeat an experiment which can end with one of 2 results (usually called a success and a failure) and want to calculate the probability of getting exactly k "success" results. If all the three try to solve the problem simultaneously, fine the probability that a) exactly one of them solves the problem b)exactly two of them solves c)none of them solves d) the problem is solved. A fair coin is tossed 5 times. Since the first child is either a boy or a girl , the second is either a boy or a girl, and the third is either a boy or a girl, the number of possible outcomes is 2⋅2⋅2 =8 by. A fair coin is tossed until a head comes up for the first time. Find the probability of getting 1 head. Find the probability of getting exactly two (3 Marks) heads. If we toss three coins (a), (b) and (c) simultaneously, there are 8 possible outcomes: Expressed as ratios, the probability of three heads is 1/8 (combination 1); of two heads and one tail 3/8 (combinations 2, 3 and 4); of one head and two tail 3/8 (combinations 5, 6 and 7); and of three tails 1/8 (combination 8). If the outcome of the first event has no effect on the probability of the second event, then the two events are called independent. Throughout we assume that the flips are independent, and in this case it is easy to show that von Neumann's procedure simulates an unbiased coin, in that one is exactly as likely to get a HEAD outcome as a TAIL outcome, no matter what the coin's bias is. 5% But I just counted on my fingers, how do you do it for big numbers?. Two coins are tossed. Figure 1: The true probability of a. ipping two coins, what is the probability that both coins will be heads. Simple numbers. Most of us miss this thing. What is the probability that: (a) We get exactly one head. COIN Three unbiased coins are tossed simultaneously: P(two head) = P(at least two head) = P(at most two head) = P(All head) = 13. Since you are trying to find the possibility of getting exactly one head, only two of the four possibilities work: HT and TH. What is the probability that at least 2 heads will occur, given that at least 1 of the first 2 tosses is a head? What is the probability that at least 2 heads will occur given that at least one head occurs?. The color of each hat is determined by [an independent] coin toss. When there coins are tossed at. Introduction to Probability and Statistics Twelfth Edition What is the probability of observing at least one head? H Toss three coins. It could be a decimal, a fraction, a percentage, or described as "one in a thousand", which is another way of writing a fraction. No Head : 128 times. Find each probability below. The probability of a certain event is 1. Thus, if we define E1 = Getting head (H) on the upper face of the coin, and, E2 = Getting tail (T) on the upper face of the coin. probability that this desperado will be the one to shoot himself dead. Therefore, a total of 4 outcomes obtained on tossing two coins simultaneously. three coins are tossed together find the probability of getting-a)exactly two heads b)at least two heads c)no head d)at least one head and one tail - Math - Cubes and Cube Roots. Using the above, nd the probability of each of the following events: (a) Getting exactly two heads. The probability of getting at least two heads when tossing a coin three. The probability of selecting one of the three doors on the game show is also equally likely. Once they have had a chance to look at the other hats [but not their own], the. a) the sample space b) the event E that the family has exactly one. Required probability = ¾. If the two indistinguishable coins are tossed simultaneously, there are just three possible outcomes, {H, H}, {H, T}, and {T, T}. Find the probability of getting: all heads (ii) two heads one head (iv) at least two heads === DOWNLOAD DOUBTNUT TO ASK ANY MATH QUESTION ===. What is the probability of obtaining at most two heads on a toss of five coins ?? - Answered by a verified Tutor We use cookies to give you the best possible experience on our website. In a lottery, there are 10 prizes and 25 blanks. e head or tail. , in short (H, H) or (H, T) or (T, T) respectively; where H is denoted for head and T is denoted for tail. you and your partner are about to toss 2 coins 100 times. The sample space S is given by S = {1,2,3,4,5,6}. If you know how to manage time then you will surely do great in your exam. Find the probability of getting exactly one head. You could save some effort by noting that all combinations with a tail in the third place cannot have a sequence of three heads, so you actually only have to write out 16 combinations (the ones with a head in the third place) and remember that the other 16 don't have any sequences of three heads. There are4 Possible Outcomes with Two Coins Tossing that is is TT,TH,HT,HH,which means one possibility is having zero heads Therefore the Probaility of this is1/4 that is25%. However, after getting our first n tosses as all heads, out new expected probability of getting a 'head' is now 1/(n+1). (b) no heads (c) exactly one head (d) exactly two heads (e) three heads Log On. Success: Tulip Matures. Two unbiased coins are tossed. You could save some effort by noting that all combinations with a tail in the third place cannot have a sequence of three heads, so you actually only have to write out 16 combinations (the ones with a head in the third place) and remember that the other 16 don't have any sequences of three heads. We toss the coin. of possible outcomes = 4 Let E = Event of getting exactly one head Outcomes favourable to E = HT, TH No. The events ‘get a head’ and ‘get a 4’ are independent events as one event does not affect the other. The chance of all three flips being tails is 1/2 * 1/2 * 1/2 = 1/8. When three coins are tossed, similarly, getting any of the side is (1/2)^3 = 1/8. Ten coins are tossed simultaneously one time = one coin is tossed 10 times. shows uncertainty in our statements. 2 for one head and he is to pay Rs. They are: HHH, HHT, HTH, THH, HTT, THT, TTH, and TTT. Note: Including the words "single time" and "after" confuse this problem somewhat. If a coin is tossed 4 times in a row then find the probability of getting exactly two consecutive heads 5. 01 The second law in probability is concerned with the sample space and the set of all outcomes within it. Find the probability that it takes at exactly 9 flips to get a run of 4 consecutive heads. 6875, or a little more than two out of three. For each player, the program counts how many tosses are needed before the "winning" sequence. Two dice are thrown simultaneously. asked by anonymous on January 18, 2018; math. Two dice are thrown simultaneously. Toss three coins 80 times. Question: What is the Probability of getting at most one head on tossing a coin? Solutions. Find the probability of getting 'Two tails'. Two fair coins are tossed simultaneously. The difference is in that in the second case we can easily differentiate between the coins: one is the first, the other second. Probability Exam - Principles of Mathmatics - Buckwalter Work must be shown to earn full credit. When three coins are tossed, similarly, getting any of the side is (1/2)^3 = 1/8. Find the probability that the number is divisible by :. Find the probability that exactly one head appears in two flips of a fair coin. Three coins are tossed once. Suppose you are trying to test whether a coin is fair—that is, whether it is equally likely to land on heads or tails. Now suppose that the coin is biased. The probability of heads is only 0. B: getting one head and two. Two coin are tossed 400 times and we get a. When a coin is tossed at random, what is the probability of getting (i) a head?. The probability of getting exactly two heads when three fair coins are thrown simultaneously is $3/8$. (Set 3) There are three coins. Find the probability of getting exactly one head. the three coins. Roll twenty times and you have a binomial distribution of (n=20, p=1/6). Find The Probability Of Getting Exactly One Head. Three coins are tossed. Three coins are tossed at the same time. The probabilities of each event - Heads and Tails - are both equal. What is the probability that: (a) We get exactly one head. Find the probability that an ace is drawn and a head is obtained on the coin (There 4 aces in a pack of cards) Two numbers are selected from the integers 1 to 11 inclusively, repeation being allowed. The second variable, p, represents the probability of one specific outcome. If the coin is fair, then by symmetry the probability of getting at least 2 heads is 50%. Question from Student Questions,math. 8 for two heads Rs. And the first question I want to ask is, what is the probability that I get exactly one head, or heads? This is one of those confusing things, when you're talking about what side of the coin. "Find the probability of more than 3 tails" which is exactly 4 tails, NOT 3 tails (all permutations), in which case rowdy you would be correct with the probability being 1/16, am I crazy or something :D But rowdy awesome on the first one, well done for spotting the mistake. Now, if a coin is tossed at random, what is the probability of getting a tail? Solution: Total number of trials = 150. e head or tail. Find the probability model for the number of coins showing heads. Following table shows the marks scored by 80 students in a mathematics test of 100 marks. What is the probability that the number thrown the second time is at least two more than the number thrown the first time?. Find the probability of getting :. 87) Three coins are tossed together. Use the rule to algebraically find the probability of getting tails on all three tosses. Find the probability that, (a) exactly two Head turns up and (b) at most two Head turns up. Find the probability of Getting only one head. In tossing three coins simultaneously, find the probability of getting 1)at least one head but at most one tail 2)at least one head but at most two heads. We toss the coin. Hope it helped you !. Toss four fair coins and find the probability of three or more heads. Chapter 8 Discrete probability and the laws of chance 8. Practice problem two. three coins are tossed together find the probability of getting-a)exactly two heads b)at least two heads c)no head d)at least one head and one tail - Math - Cubes and Cube Roots. That is because Heads and Tails are equally likely. What is the probability that the rst 100 produced are not defective? 2. Number of times head appeared = 71. If you flip it 5 times, you have 2^5=32 possible outcomes. We say that the probability of an event A occuring is P(A)= Number of elements in A Total number of elements in the sample space Example If a fair coin is tossed, it is clear from our definition of probability above that P (obtaining a head) = 1 2. a) What is the probability of getting a jack and then an eight? Ans: 1/169 b) What is the probability of getting a diamond and then a heart? Ans: 1/16 Example 2. Find probability of: (a) 3 heads (b) exactly 2 heads (c) atleast. A box contains 3 coins, a normal coin , a doubly headed coin and a biased coin with P(H) = 1/3. And this time, instead of flipping it four times, let's flip it five times. GRE Math — The Probability of a Coin Toss By Chris Lele on April 9, 2011 , UPDATED ON June 15, 2018, in GRE Data Analysis , GRE Math If rate problems bring to mind moving trains, then there is no more iconic type of probability question than the coin toss. 2 What is the probability of getting three or more heads in a row. The gure below show the 52 playing card in standard decl. Two coins are tossed simultaneously. "Find the probability of more than 3 tails" which is exactly 4 tails, NOT 3 tails (all permutations), in which case rowdy you would be correct with the probability being 1/16, am I crazy or something :D But rowdy awesome on the first one, well done for spotting the mistake. Solution: ∵ A coins has two faces Head and Tail or H, T ∴ Two coins are tossed ∴ Number of coins = 2 x 2 = 4 which are HH, HT, TH, TT. Here H denotes head and T denotes tail. The probability that you win $4 both times is. In the second tossing of coins two coins were tossed 40 times simultaneously from BIO 214 at Ball State University. The probability of selecting one of the three doors on the game show is also equally likely. Tossing a coin three times 📌 Ex10. flip a coin and record Head or Tail, then choose a ball from an urn and record its color The branches emanating from any point on a tree diagram must have probabilities that sum to 1. Find the probability that exactly two of the people flipped one head and one tail. Algebra -> Probability-and-statistics-> SOLUTION: Three fair coins are tossed. Comment( 0 ). The third row says that if we toss three coins, we have one chance of getting all heads, three chances of getting one head and two tails, three chances of getting two heads and one tail, and one chance of getting three tails. Describe (i) Two events which are mutually exclusive. 5 we get this probability by assuming that the coin is fair, or heads and tails are equally likely. Find the probability of getting an ace. one head: HTT or THT or TTH = 3C1 = one of these 3ways the event can happen. Because they are equal, they are both given a probability of ½. Suppose that we tossed three coins 800 times. In the second tossing of coins two coins were tossed 40 times simultaneously from BIO 214 at Ball State University. 3 heads ii. Find the probability of getting : (i) 2 heads (ii) atleast one head 2. 25 If the coin is tossed 7 times, there are 2^7 = 128 possible outcome, and just one of them is all heads. COIN Four or More Coins are tossed?? You need Binomial for that. Find the probability to get (i) exactly two heads (ii) at most two heads (iii) at least two heads. If the probability that an event will occur is "x", then the probability that the event will not occur is "1 - x". Answered by Robert Dawson. Hope it helped you !. The coin is flipped 10 times and the result of each flip is noted. Since 1 head occurs for simple events HT and TH, A={HT,TH} we get P (1 head) = 2/4=1/2. Three coins are tossed simultaneously p is the event of getting at. Example 8: A die is rolled, find the probability of getting an even number. If the outcomes of the two coin tosses are the same, we win; otherwise, we lose. Then repeatedly toss the coin eight times in a row until one of the declared 36 strings occurs, and take the corresponding pair to be the roll of the two dice. Next suppose we toss a coin. Note "Au B" or AB represent the occurrence of either A or B. Find The Probability Of Getting Exactly One Head. And the first question I want to ask is, what is the probability that I get exactly one head, or heads? This is one of those confusing things, when you're talking about what side of the coin. e head or tail. Manually going through the combinatorics to determine the probability of an event occuring If you're seeing this message, it means we're having trouble loading external resources on our website. (vi) A coin is tossed and a die is thrown simultaneously : P is the event of getting head and a odd number. The probability of getting exactly two heads when three fair coins are thrown simultaneously is $3/8$. of students 5 8 10 18 15 18 6 Marks 020 2030 3040 4050 5060 6070 70100 Find the probability that a student obtained: (i) less than 40% marks. While we don’t know whether the coin prefers heads or tails, we do know that each flip is independent, so we. (b) no heads (c) exactly one head (d) exactly two heads (e) three heads Log On. When they land on the chair below, find the odds (a) in favor of getting exactly three heads (b) in favor of getting exactly three tails (c) against. A machine manufactures ra ators, and, on average, one in 1000 is defective. a) What is the probability of getting a jack and then an eight? Ans: 1/169 b) What is the probability of getting a diamond and then a heart? Ans: 1/16 Example 2. Three coins are thrown simultaneously, find the probability of getting two heads and one tail. If two coins are flipped, it can be two heads, two tails, or a head and a tail. of possible outcomes = 4 Let E = Event of getting exactly one head Outcomes favourable to E = HT, TH No. Find the probability of getting a prize. First, consider all the ways that the three coins could land: For each coin, there are two possibilities, heads or tails, so for the three coins, the number of possibilities is: 2 x 2 x 2 = 8 possibilities i. Expected Tosses for Consecutive Heads with a Fair Coin Date: 06/29/2004 at 23:35:35 From: Adrian Subject: Coin Toss What is the expected number of times a person must toss a fair coin to get 2 consecutive heads? I'm having difficulty in finding the probabilty when the number of tosses gets bigger. If three unbiased coins are tossed simultaneously, then the probability of exactly two heads, is. Hence the probability of getting a 3 is P(E) = 1 / 6. Find the probability of landing on the head side of the coin and rolling a 3 on the die. First, note that the problem will likely make reference to a "fair" coin. So the probability of getting two heads is 25% or 1/4. A coin is tossed 150 times and head is obtained 71 times. Comment( 0 ). (H,T) shows that on coin 1 it’s Head while on coin 2 it’s Tail. probability that this desperado will be the one to shoot himself dead. ) So the probability of the event "exactly 1 head appears" is 3/8. Use H to represent a boy birth, and T to represent a. (c) We get at most one head. For Event A. a) What is the probability of getting a jack and then an eight? Ans: 1/169 b) What is the probability of getting a diamond and then a heart? Ans: 1/16 Example 2. Find the probability that (i) A wins all the three games (ii) 2 of the games end in a draw. of favorable outcomes = 2 Probability (E) = Number of favourable outcomes / Total number of outcomes. Write all the possible outcomes. If we call the coins A, B, C and D, there are four different ways to get exactly three tails (A lone is heads, B alone is heads, C alone is heads ) and there is one way to get all tails. Note that the last three cases for the coins chosen expand into eight different cases when we care whether coin 2 or coin 3 is chosen. To find the total probability of this event, we need to add the probability of the different outcomes that correspond to this event. Toss the coin twice and there are 4 (2^4)possible outcomes, HH, HT, TH, TT. Q-Three coins are tossed once. If the probability that an event will occur is "x", then the probability that the event will not occur is "1 - x". You observe that it comes up heads. The objective is to find the probability that the outcome is three heads. Find the probability function of the random variable X = Number of heads and compute the probabilities of obtaining no heads, precisely 1 head, at least 1 head, not more than 4 heads. that Kerry does not get an "A?". C be the event of getting at. We toss two fair coins simultaneously and independently. These are mutually exclusive, each one has a probability of of one eighth, as we just figured out, so we add them, and so this adds up to a grand total of 3/8, and that is the probability of flipping three fair coins and getting exactly two heads. Five fair coins are tossed simultaneously.