Customers Are Serviced at a Rate of Four Customers Per

Multiple Choice

Customers are serviced at a rate of four customers per hour according to an exponential distribution. What is the probability that customer service will require fewer than 30 minutes?

A) less than or equal to 0.50
B) greater than 0.50 but less than or equal to 0.60
C) greater than 0.60 but less than or equal to 0.70
D) greater than 0.70