The mean gas mileage for a hybrid car is 56 miles per gallon. suppose that the gasoline mileage is approximately normally distributed with a standard deviation of 3.2 miles per gallon.

(a) what proportion of hybrids gets over 60 miles per gallon?
(b) what proportion of hybrids gets 52 miles per gallon or less?
(c )what proportion of hybrids gets between 57 and 62 miles per gallon?
(d) what is the probability that a randomly selected hybrid gets less than 45 miles per gallon?