A vegetable distributor knows that during the month of August, the weights of its tomatoes are normally distributed with a mean of 0.61 lb and a standard deviation of 0.15 lb. (See Example 2 in this section.)

a) What percent of the tomatoes weigh less than 0.76 lb?

b) In a shipment of 5,000 tomatoes, how many tomatoes can be expected to weigh more than 0.31 lb? C) In a shipment of 4,500 tomatoes, how many tomatoes can be expected to weigh from 0.31 lb to 0.91 lb?