Question

1. QSR Magazine studied drive through times for fast-food restaurants and found that Wendy’s has the best time, with a mean of 138.5 seconds and a standard deviation of 29 seconds. Wendy’s institutes a policy at its restaurants that it will not charge any patron that must wait more than a certain amount of time for an order. Management does not want to give away free meals to more than 1% of the patrons. What time would you recommend Wendy’s advertise as the maximum wait time before a free meal is awarded?

Answer 1

This is a normal distribution question with

Top 1% means 99percentile
Given in the question
P(X < x) = 0.99
This implies that
P(Z < 2.3263) = 0.99
With the help of formula for z, we can say that

x = 205.9641
PS: you have to refer z score table to find the final probabilities.
Please hit thumbs up if the answer helped you