Question

The average travel time from your residence to your school is 35 minutes with a standard deviation of 10 minutes. If you want to be 99% certain that you will not be late for first 8:00 am class, what is the latest time you should leave home?

Answer 1

$P(Z<z)=0.99.$

$z=2.326.$

$\frac{x-35}{10}=2.326.$

$x=2.325*10+35=58.25.$

The latest time you should leave home: $8:00-58.25=7:01.75\approx7:02.$