This is the same as that exactly three heads come up in the 2nd through 5th

flip. The number of heads in these 4 flips ~B(4,0.5), so is:

p = prob(4 H from 5 flips|first is H) = b(3;4,0.5)

Now look the probability mass function for the binomial distribution up in your

notes and/ot text to evaluate p.

RonL