Dawes Designs buys T$-$shirts for clubs, teams, and other organizations. Dawes takes the shirts and adds the organization's logo$.$ Because of the uncertainty in the timing of the sales and to avoid stock outages, Dawes tries to maintain an inventory of shirts equal to two$-$month's of sales. The shirts cost $$8\mathrm{.}50$ each and must be paid for in cash. On June $30$ of the current year, the company expects to have $15,800$ shirts in stock. Sales estimates, based on contracts received and historical data, are as follows for the next six months:

July $7,220$

August $10,190$

September $7,660$

October $8,210$

November $5,680$

December $4,360$

Required:

a$.$ & b$.$ Estimate purchases $($in units$)$ and cash required to make purchases in July, August, and September.