Okay, lets write out the possible outcomes when flipping a coin 3 times:
HHH, HHT, HTH, THH, TTH,THT,HTT,TTT
That constitures 8 scenarios in which the coin can fall over a 3 flip trial.
Now, it is known that you got "at least one head" so therefore we can rule out the no head scenario (TTT) which leaves us with 7.
Of those 7 times, how many times does it fall heads exactly twice?
Well, we have HHT,HTH,THH.
From this you can say that it there are 3 possible outcomes in which you get exactly two heads given that you get at least one head. 3/7.
The probability of flipping Heads on a coin is 1 - a certainty - if the coin is flipped often enough. On a single toss of a fair coin the probability is 1/2.
The probability of flipping a quarter and getting heads is 1 in 2. the probability of rolling a die and getting 6 is 1 in 6.
The probability of flipping a coin 3 times and getting 3 heads is 1/2
The probability of throwing exactly 2 heads in three flips of a coin is 3 in 8, or 0.375. There are 8 outcomes of flipping a coin 3 times, HHH, HHT, HTH, HTT, THH, THT, TTH, and TTT. Of those outcomes, 3 contain two heads, so the answer is 3 in 8.
The best way to think about this is the following way: What is the probability of flipping heads once? 1/2 What is the probability of flipping heads twice? 1/4 (1/2 * 1/2) Using this we can derive the equation to find the probability of flipping heads any number of times. 1/2n Using this we plug in 25 for n and get 1/225 or as a decimal 2.98023224 x 10-8 or as odds 1:33,554,432
The probability is 0.375
50-50
The probability of flipping Heads on a coin is 1 - a certainty - if the coin is flipped often enough. On a single toss of a fair coin the probability is 1/2.
The answer is 1/2 , assuming the coin is fair.
The probability of rolling a 2 on a die before flipping a heads on a coin is 1 in 12. The probability of rolling a 2 is 1 in 6. The probability of flipping heads is 1 in 2. Since these are sequentially unrelated events, you simply multiply the probabilities together.
The probability of flipping a quarter and getting heads is 1 in 2. the probability of rolling a die and getting 6 is 1 in 6.
The probability of flipping a coin 3 times and getting 3 heads is 1/2
The probability of throwing exactly 2 heads in three flips of a coin is 3 in 8, or 0.375. There are 8 outcomes of flipping a coin 3 times, HHH, HHT, HTH, HTT, THH, THT, TTH, and TTT. Of those outcomes, 3 contain two heads, so the answer is 3 in 8.
The probability of this is 50%. 2/4
There are 8 permutations of flipping a coin 3 times, or of flipping 3 coins one time. They are, with the permutations of two heads bolded...TTTTTHTHTTHHHTTHTHHHTHHH... thus, the probability of flipping a coin 3 times and getting 2 heads is 3 in 8, or 0.375.
The best way to think about this is the following way: What is the probability of flipping heads once? 1/2 What is the probability of flipping heads twice? 1/4 (1/2 * 1/2) Using this we can derive the equation to find the probability of flipping heads any number of times. 1/2n Using this we plug in 25 for n and get 1/225 or as a decimal 2.98023224 x 10-8 or as odds 1:33,554,432
We have no way of knowing the probability of any given person flipping any given coin at any given time. But for any two flips of an honest coin, the probability that both are tails is 25% . (1/4, or 3 to 1 against)