Question

A company has a policy of retiring company cars; this policy looks at number of miles driven, purpose of trips, style of car and other features. The distribution of the number of months in service for the fleet of cars is bell-shaped and has a mean of 63 months and a standard deviation of 10 months. Using the 68-95-99.7 rule, what is the approximate percentage of cars that remain in service between 73 and 83 months?

Answer 1

cars in service after 73 months ... (100% - 68%) / 2

cars in service after 83 months ... (100% - 95%) / 2

take the difference to find the desired percentage

Answer 2

13.5