Ahmed wants to earn some extra pocket money while on his summer break, which is 5 weeks long. He plans to work for three days a week and enjoy his vacation the rest of the week. He has identified that car cleaning is a good business in his locality. He buys a trolley for $500 to carry water, detergent, brushes, towels, and other items, and he spends about $2 per car on these items.

a. If Ahmed charges $10 to clean one car, how many cars would he need to clean to breakeven?
b. If Ahmed cleans about 10 cars per day, how much money does he expect to make?
c. Another possibility for Ahmed is to clean the open parking lots (areas, not cars). To do this, he need to hire a truck for $1,500 and hire a driver on an hourly basis, which, including gas, would cost him about $25 per parking lot. Ahmed estimates that the truck helps him complete four parking lots per day. If he charges $125 per parking lot, would this be a better alternative than cleaning cars?