If the probability of rain on any given day in Chicago during the summer is 50%, independent of what happens on any other day, what is the probability of having exactly 3 rainy days from July 4 through July 7, inclusive?	Choose the most appropriate option:
A) 1/4  B) 1/8  C) 3/8  D) 3/16  E) 5/16
One case is rainy-rainy-rainy-not rainy.   The probability of this case is (1/2)^4 = 1/16   The number of possible cases is 4C3 = 4.   P(exactly 3 rainy days) = 4*1/16 = 1/4   The answer is 1/4.
<result>A</result>
If the probability of rain on any given day in Chicago during the summer is 50%, independent of what happens on any other day, what is the probability of having exactly 3 rainy days from July 4 through July 7, inclusive?