On June 30 of the current year, the company expects to have 16,400 shirts in stock. Sales estimates, based on contracts received and historical data, are as follows for the next six months:\ \ July 7,820\ August 10,790\ September 8,260\ October 8,810\ November 6,280\ December 4,960\ Required:\ a. & b. Estimate purchases (in units) and cash required to make purchases in July, August, and September.