Some students held a car wash to raise money for a field trip. they charged $5 to wash each car. the students made a profit of $853 after they spent $12 on supplies for the wash. how many cars did they wash? show all your work and explain why you did each step.

So, we have to divide the total amount of the profit they made by the cost per car wash. This is because we have to find the unit rate. So, the problem would be $853 divided by $5. Now the answer would be 170.6, but if you round the answer, it would be approximately 170 cars. We have to round, because 0.6 is NOT a full car, and we need to know how MANY CARS were washed. We wouldn't do anything with the $12 they spent, because the problem does NOT state anything about the amount of cash they have AFTER the supplies were bought.