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 1,000 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) No, because Mark will only save about $90 dollars in gas over the four years but the new tires will only be $100 more.

Question

Quizplus · Accepted Answer

With the new tires, Mark's car would get 36 miles per gallon (a 20% increase from 30 mpg). Over 48,000 miles, he would need 1,333.33 gallons of gas with the old tires (48,000 miles / 30 mpg) and 1,111.11 gallons with the new tires (48,000 miles / 36 mpg), saving 222.22 gallons. At $2.50 per gallon, he saves $555.55 on gas. The new tires cost $100 more in total ($25 more per tire), so he saves about $455.55 overall, making option A the closest correct choice despite the slight discrepancy in the savings calculation presented in the question.

Mark Must Buy Four New Tires for His Car