Probability
posted by Anonymous .
Two fair coins are flipped simultaneously. This is done repeatedly until at least one of the coins comes up heads, at which point the process stops. What is the probability that both coins come up heads?
I think it would be 1/2 but the answer is 1/3 and I have no idea where you would get that answer.

Three things can happen with equal probability on the fateful toss when "at least one" is heads:
Coin A heads; Coin B heads
Coin A heads, Coin B tails
Coin A tails; Coin B heads
That makes one out of three with both heads 
Bob flipped a coin 200 times with the following results:120 heads, 80 tails. Based on these results what is the experimental probability that Bob will get a tail on the next flip.
Respond to this Question
Similar Questions

math
Six fair coins are flipped, the probability that exactly three coins turns up heads is T. If the coins are flipped again, the probability that exactly 16T coins turns up heads is S. If the six coins are flipped again, the probability … 
MathProbability
Consider a collection of n biased coins, each showing Heads with probability p and Tails with probability 1p , independently of the others. The coins are tossed and all coins showing Heads are collected together and tossed again. … 
mathematics
John has 3 unique coins such that the probability of obtaining a head when the coin is flipped is 110, 210 and 310, respectively. If he flips each of the 3 coins once, the probability that at least 1 heads appears is p. What is the … 
math
John has 3 unique coins such that the probability of obtaining a head when the coin is flipped is 1/10, 2/10 and 3/10, respectively. If he flips each of the 3 coins once, the probability that at least 1 heads appears is p. What is … 
probability
John has 3 unique coins such that the probability of obtaining a head when the coin is flipped is 110, 210 and 310, respectively. If he flips each of the 3 coins once, the probability that at least 1 heads appears is p. What is the … 
probability
John has 3 unique coins such that the probability of obtaining a head when the coin is flipped is 1/10, 2/10 and 3/10, respectively. If he flips each of the 3 coins once, the probability that at least 1 heads appears is p. What is … 
mathsurgent
a man has 3 unique coins such that the probability of obtaining a head when the coin is flipped is 1 10 , 2 10 and 3 10 , respectively. If he flips each of the 3 coins once, the probability that at least 1 heads appears is p . What … 
math
John has 2 coins, one fair and the other unbalanced so that the probability of its coming up heads is 2/3. He picks one of the coins at random, tosses it, and it comes up heads. What is the probability that he picked the unbalanced … 
Math
Four coins fall onto the floor. Find the probability that (a) exactly three coins land heads up (b) all coins land tails up (c) two or more coins land heads up (d) no more than two coins land tails up (e) at least one coin lands tails … 
Math
Darrin tosses a quarter and a penny 20 times. He gets heads on both coins twice. Compare the theoretical probability of getting heads on both coins with Darrinâ€™s experimental probability of getting heads on both coins. Why might …