5. A highway department has enough salt to handle a total of 80 inches of snowfall.

Suppose the daily amount of snow has a mean of 1.5 inches and a standard deviation of .3 inches.

(a) Approximate the probability that the salt on hand will suffice for the next 50 days.

(b) What assumption did you make in solving part (a)?

(c) Do you think this assumption is justified? Explain briefly.