2 My dog just had 3 frisky puppies who jump in and out of their whelping box. A puppy spends an average of 10 minutes (exponentially distributed) in the whelping box before jumping out. Once out of the box, a puppy spends an average of 15 minutes (exponentially distributed) before jumping back into the box.

a At any given time, what is the probability that more puppies will be out of the box than will be in the box?

b On the average, how many puppies will be in the box?