Each time the frozen yogurt machine at the mall breaks down, it is replaced by a new one of the same type.

(a)What is the limiting age distribution for the machine
in use if the lifetime of a machine has a gamma(2,\lambda) distribution, i. e., the sum of
two exponentials with mean 1=\lambda.

(b) Find the answer to (a) by thinking about a rat one Poisson process in which arrivals are alternately colored red and blue.