i really don't understand. i tried figure out. i started with the first charges: sqrt[2(20)(100))/0.05}

Question

Suppose you have a choice of three suppliers for footballs. the first charges $100 per delivery but won't deliver more than 200 at a time; the second charges $100 also but won't deliver less than 300; the third will deliver any quantity but charges $200. Which supplier should you use? In all cases r = 20 and s=$0.05