[求助]GWD-12-17

tiy

Q17:

If a certain coin is flipped, the probability that the coin will land heads is 1/2.  If the coin is flipped 5 times, what is the probability that it will land heads up on the first 3 flips and not on the last 2 flips?

A.          3/5

B.          1/2

C.          1/5

D.          1/8

E.          1/32

answer: B

narcisuss

答案错？

怎么想都是E。

tiy

E该如何得出呢？