8 An order office receives 20 faxed orders every hour What i

8. An order office receives 20 faxed orders every hour.

What is the probability that more than 12 minutes will elapse between faxed orders?

Solution

As the office receives 20 faxes orders every hour so the time between receiving an order follows an Exponential distribution with mean 1/20.

The required probability,

P(X>12)=e^(-12*1/20)=0.54881