An oil change company advertises that they can change the oil in your car in 15 minutes. Based on the data collected below, what is the probability that oil change will take more than 15 minutes?

Class Interval
Frequency
6 to 10 minutes
3
11 to 15 minutes
8
16 to 20 minutes
6
21 to 25 minutes
2
More than 25 Minutes
1

(6+2+1)/(6+2+1+8+3) = ?