A car needs fixing and Abe can fix it for $70 per hour with a $130 part, but Gabe can fix it for $80 an hour with a $40 part. How long will it take for both Abe and Gabe to cost the same amount?

9 hours

Step-by-step explanation:

Abe's charge = Gabe's charge

$130 + ($70/hr) h = $40 + ($80/hr) h

Then 130 + 70h = 40 + 80h, or

90 = 10h, or h = 90/10 = 9

When 9 hours have passed, the amount charged by each person will be temporarily equal.