The average cost for a used car dealer for minor repairs under a 90-day warranty is $20. How many can occur in a month if the car dealer is to lose at most $440

Question

The average cost for a used car dealer for minor repairs under a 90-day warranty is $20. How many can occur in a month if the car dealer is to lose at most $440

Answer 1

First, it is important to understand that the warranty forces the dealership to preform $20 repairs for free. So each time they preform one, they "lose" $20.

 

Also, the question asks, "How many repairs," so we need a variable for the number of repairs.

"NUMBER OF REPAIRS" = R

 

Let's try to write an equation for cost in terms of the number of repairs. The question is, "How many twenty dollar repairs are worth $440" That translates to the equation:

 

$20R = $440

 

Division by $20 on each side yeilds

 

R = 22

 

Notice that the division operation canceled the "$" units.

 

So, 22 repairs would typically cost $440. Any more, and they would lose more money, but making fewer repairs is just fine. The answer is 22 repairs.