The time (in minutes) between telephone calls at an insurance claims office has the following exponential probability distribution. f(x)=0.50e -0.50x for x>=0 a. What is the mean time between...

The time (in minutes) between telephone calls at an insurance claims office has the following

exponential probability distribution.

f(x)=0.50e^-0.50x        for x>=0

a. What is the mean time between telephone calls?
b. What is the probability of having 30 seconds or less between telephone calls?
c. What is the probability of having 1 minute or less between telephone calls?
d. What is the probability of having 5 or more minutes without a telephone call?