1) 550 x 15 = 8250 (First you want to get the total cost of the computers)
2) 30,000 - 8250 = 21,750 (Then you want to subtract that by 30,000 to see how much money is left over)
3) 21,750/6 = 3625 (Then divide by 6 ,by the weeks, and get your answer)
Answer: $3625