Question

Jeff typically makes three out of nine attempted free throws. What's the average waiting-time for Jeff to make his first basket, and what's the probability he'll make a basket on or before the very last attempt within his average waiting-time?

A. 3, 0.7

B. 6, .94

C. 3, 15

D. 9, .97

E. 3, 33

Answer 1

The average waiting-time for Jeff to make his first basket can be calculated by taking the reciprocal of his success rate, which is 1/3 or 3 attempts.

The probability that Jeff will make a basket on or before the very last attempt within his average waiting-time can be calculated by subtracting the probability that he won't make a basket within that time from 1. The probability that he won't make a basket within 3 attempts is (2/3)^3 or 8/27. So, the probability he will make a basket on or before the last attempt is 1 - 8/27 = 19/27 or approximately 0.70.

Therefore, the correct answer is:

A. 3, 0.7