The chance of rain on any given day in Tel-Aviv is 50%. What is the probability W that it rained in Tel-Aviv on exactly 4 out of 6 randomly chosen days?
Choose the correct choice:  A) 15 / 64  B) 30 / 64  C) 1 / 2  D) 1 / 4  E) 52 / 64

Rationale: chances of rain on exactly 4 days and not rain on 2 days = ( 1 / 2 ) ^ 4 * ( 1 / 2 ) ^ 2 = 1 / 64 chosing 4 days out of 6 = 6 ! / ( 4 ! * 2 ! ) = 15 chances of rain on exactly 4 days out of 6 days w = 15 / 64 ans a it is .
Answer: A