Average sales for an online textbook distributor were $74.37 per customer per purchase. Assume the sales are normally distributed. If the standard deviation o the amount spent on textbooks is $8.57, find the percentage of customers of the online textbook distributor that spent: (a) more than $91.51 per purchase. (b) less than $82.94 per purchase. Round your answer to the nearest tenth of a percent. Refer to the table of values (& Area Under the Standard Normal Distribution) as needed. Part: 0 / 2 Part 1 of 2 (a) The percentage of customers that spent more than $91.51 per purchase is X