The classes at the middle school want to raise money. the sixth grade runs a bake sale for 55 hours and makes $170. the seventh grade sets up a dunking booth for 44 hours and makes $112. the eighth grade has a car wash and makes $192 in 66 hours. which class has the highest rate for raising money?

The sixth grade runs a bake sale for 55 hours and makes $170.
So in one hour, they made 170/55 = 3.09 dollars.
Rate: $3.09/h

The seventh grade sets up a dunking booth for 44 hours and makes $112.
So in one hour, they made 112/44 = 2.54 dollars.
Rate: $2.54/h

The eight grade has a car wash and makes $192 in 66 hours.
So in one hour, they made 192/66 = 2.90 dollars.
Rate $2.90/h

3.09 > 2.90 > 2.54
So R(6th) > R(8th) > R(7th)

Which means that the sixth grade has the highest rate for raising money.

Hope this helps! :)

The rate of sixth grade is 170/55 = $3.09/hr.
The rate of seventh grade is 112/44 = $2.54/hr.
The rate pf eighth grade is 192/66 = $2.90/hr.
=> The sixth grade has the highest rate.