Cars arrive randomly at an intersection with an average traffic volume of one car per minute. The likelihood, or probability, that at least one car enters the intersection during a period of x minutes can be estimated by f(x) = 1 = e^-x 

(a) What is the probability that at least one car enters the intersection during a 5-minute period?

(b) Determine the value of x that gives a 40% chance that at least one car enters the intersec- tion during an interval of x minutes.