A store opens at 8 A.M. From 8 A.M. until 10 A.M. customers arrive at a Poisson rate of

6 per hour. Between 10 A.M. and 12 P.M. they arrive at a Poisson rate of 10 per hour. From 12

P.M. to 2 P.M. the arrival rate increases steadily from 10 per hour at 12 P.M. to 20 per hour at 2

P.M., and from 2 P.M. to 5 P.M. the arrival rate drops steadily from 20 per hour at 2 P.M. to 5

per hour at 5 P.M. Determine the probability distribution of the number of customers that enter

the store on a given day.