a school is planning a car wash to raise $600. how much should the school charge per car to raise exactly $600

Question

• there will be 8 teams
• each team will wash 2 cars per hour
• the car was will last 5 1/2 hours
• each team will take two 15-minute breaks

Answer 1

For each team:

"the car wash will last 5 1/2 hours"

"each team will take two 15-minute breaks"    (that's  1/2 hour)

So, Each team works 5 hours.

 

"each team will wash 2 cars per hour"

That's 10 cars per team.        [5*2]

 

"there will be 8 teams"

That means 80 cars will get washed (assuming there is a constant line of cars)     [10*8]

 

To earn $600, the charge must be $600/80= $7.50 per car.

 

Check (very important):

  "each team will wash 2 cars per hour"   so each team earns $15 per hour

  "the car wash will last 5 1/2 hours" and "each team will take two 15-minute breaks"

         so, 5*$15 = $75 earned per team

  "there will be 8 teams"   means the car wash earned 8*$75 = $600

 

Answer 2

Each team takes 2 x 15 minute breaks = 30 min/team.

30 min/team x 8 teams = 240 min = 4 hours break time

Total hours worked =5.5 hours - 4 hours break = 1.5 hours

1.5 hours/team x 8 teams x 2 cars/hour = 24 cars washed

$600/24 cars = $25 per car