SOLUTION: a fair coin is tossed 3 times, 1. what's the probability of getting two heads? 2. what's the probability of getting three heads? 3. what's the probability of getting number of h

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Question 253224: a fair coin is tossed 3 times,
1. what's the probability of getting two heads?
2. what's the probability of getting three heads?
3. what's the probability of getting number of heads greater than number of tails?
Found 2 solutions by richwmiller, Edwin McCravy:
Answer by richwmiller(17219) (Show Source):
You can put this solution on YOUR website!
probability of one head is 50%=.5=1/2
1.-two heads 1/2*1/2
2.-three 1/2*1/2*1/2
3. - I don't know. I'll have to think about that one. There are some tutors here who are very good at probability

Answer by Edwin McCravy(20056) (Show Source):
You can put this solution on YOUR website!
a fair coin is tossed 3 times,
1. what's the probability of getting two heads (exactly)?
2. what's the probability of getting three heads?
3. what's the probability of getting number of heads greater than number of tails?

Sample Space 2 heads (exactly)? 3 heads? More heads than tails? ---------------------------------------------------------------- HHH NO YES YES HHT YES NO YES HTH YES NO YES HTT NO NO NO THH YES NO YES THT NO NO NO TTH NO NO NO TTT NO NO NO result 3 out of 8 1 out of 8 4 out of 8 P(2 heads) = 3/8 P(3 heads) = 1/8 P(more heads than tails) = 4/8 = 1/2 Also you can do this using binomial formulas: P(2 heads) = P(3 heads) = P(more heads than tails) = P(2 heads OR 3 heads) = P(2 heads) + P(3 heads) = .375 + .125 = .5 Edwin