What is the difference between lorenz curve and Z curve

Fanning books buys books and magazines directly from publishers and distributes them to grocery stores. the wholesaler expects to purchase the following inventory: april may june required purchases (on account) $ 111,000 $ 131,000 $ 143,000 fanning books accountant prepared the following schedule of cash payments for inventory purchases. fanning books suppliers require that 85 percent of purchases on account be paid in the month of purchase; the remaining 15 percent are paid in the month following the month of purchase. required complete the schedule of cash payments for inventory purchases by filling in the missing amounts. determine the amount of accounts payable the company will report on its pro forma balance sheet at the end of the second quarter.