Keep the old car or buy a used car manny is an online student who currently owns an older car that is fully paid for. he drives, on average, 110 miles per week to commute to work. with gas prices currently at $2.51 per gallon, he is considering buying a used fuel-efficient car, and wants to know if it would be good financial decision. the old car manny owns currently gets 20 miles per gallon for average fuel efficiency. it has been a great vehicle, but with its age, it needs repairs and maintenance that average $620 per year (as long as nothing serious goes wrong) he is considering buying a newer used car that will cost a total of $5,500 over a three-year loan process. the used car gets 33 miles per gallon and would only require an average of $30 per month for general maintenance. to make a decision manny wants to calculate the total costs for each scenario over three years. he decides to use the quantitative reasoning process to do this.