Question

The manager of a grocery store estimates that 74% of customers will make a purchase.

Part A: How many customers should a cashier expect until he finds a customer that makes a purchase?



Part B: What is the probability that a cashier helps 3 customers until he finds the first person to make a purchase?

Answer 1

I know part B: 4.69%

P(y=k)=(1-p)^k-1 p

I have yet to figure out A but I know their answer is wrong for B

Explanation:

Its out of 3 not 100. So you have to fill the numbers into the equation.