The time in minutes until the next bus departs a major bus d

The time (in minutes) until the next bus departs a major bus depot follows a uniform distribution from 21 to 44 minutes. Let X denote the time until the next bus departs.

The distribution is

The mean of the distribution is =T

he standard deviation of the distribution is =

The probability that the time until the next bus departs is between 30 and 40 minutes is P(30<X<40)=  

Ninety percent of the time, the time to the next departure is less than how many minutes? That is, P(Xa)=0.9   for   a=

Solution