Question

Chris works at a tire store. Chris can change a tire on a rim in 8 to 12 min, with all times in between equally likely. A) What is a probability that Chris changes a given tire in less than 9 min? b) What is the probability that it takes between 9 min and 11. 5 min? c) What is the probability that it takes exactly 10 min?

Answer 1

He can change a tire in 8,9,10,11 to 12 minutes.
So these 5 times are equal to 20% each.

A) Less than 9 minutes means 8 minutes, so 20%.
B) If each minute is equal to 20%, 2.5 minutes (11.5 - 9) are 50%.
C) 20%.