If each team takes two 15 minute breaks, then for 1/2 an hour of the 5.5 hours, is not used. So they only worked 5 hours. If each team washed 2 cars per hour, then each team washed 10 cars. Since there are 8 teams, 80 cars were washed during the car wash. If they plan to raise $600, then you can divide 600 by 80 to get the minimum price they need to charge or $7.5. Each team should charge the cars at least $7.50.