Question

Arnold is about to go on a 500-mile car trip. His mechanic recommends that he buy

a special highway engine oil that will save him 50 cents in gas for every 25 miles of the
trip. This new oil, however, will cost $20. Is it worthwhile for Arnold to buy the oil if he
has a coupon for $4 dollars off the price?

Answer 1

500 miles/ 25 = 20 x 0.50 = $10

He will save a total of $10

20-4 = $16

it will cost him $16 for the oil which is more than what he saves in gas so buying the oil is not worth it.