Mark must buy four new tires for his car. He is considering buying tires that are $25 a piece more than his regular brand, because the higher priced tires are supposed to increase his miles per gallon by 20%. If the tires are good for 48,000 miles and Mark drives an average of 1000 miles per month, gas costs $2.50 per gallon over the next 4 years, and Mark's car gets 30 miles to the gallon now (on the old tires), should Mark purchase the more expensive tires?
A) Yes, because Mark will save about $660 dollars in gas over the four years but the new tires will only be $100 more.
B) Yes, because Mark will save about $560 dollars in gas over the four years but the new tires will only be $100 more.
C) No, because Mark will only save about $60 dollars in gas over the four years but the new tires will only be $100 more.
D) There is not enough information given in the problem to make the decision.

Question

Quizplus · Accepted Answer

The new tires increase fuel efficiency by 20%, so Mark's car will get 36 miles per gallon. Over 48,000 miles, he will use 1,333.33 gallons with the new tires, compared to 1,600 gallons with the old tires. This saves 266.67 gallons, which at $2.50 per gallon saves $666.67. The new tires cost $100 more, so the net savings is about $566.67, making option A correct.

Mark Must Buy Four New Tires for His Car