Answer: option d.
Step-by-step explanation:
You have the following formul given in the problem:
You know that:
The number of customers serviced in an hour by the technical support representative is 6 costumbers, therefore:
As the problem asked for the probability that a costumber will be on hold less than 30 minutes, we know that:
Substitute the values above into the formula.
Then, you obtain:
or 95%