Question

Two cars got an oil change at the same auto shop. The shop charges customers for each quart of oil plus a flat fee for labor. The oil change for one car required 5 quarts of oil and cost $21.90. The oil change for the other car required 7 quarts of oil and cost $25.40. How much is the labor fee and how much is each quart of oil?

Answer 1

Explanation:

Let x = the fee and let y = the cost per quart of oil

x + 5y = 22.45

x + 7y = 25.45 Multiply this equation by (-1) and add it to the 1st equation

-x -7y = -25.45

x + 5y = 22.45

-2y = -3

y = $1.50 /quart

x + 5(1.50) = 22.45

x + 7.50 = 22.45

x = $14.95 is the basic fee