Sally needs a new car. She is trying to lessen her "carbon foot print", but at the same time she wants to spend her money wisely.

Question

She is deciding between the Lexus RX 450h (hybrid) and the Lexus RX 350. The RX450h costs $43,700 with anticipated gas costs of $1,454 per year. The RS 350 costs $38,650 with anticipated gas costs of $2,078 per year. How many years will it take for the total costs of the two SUVs to be the same?

Answer 1

If x is the number of years and y is the total cost, the 2 models che be written as:

y = 43700 +1454 x and

y = 38650 + 2078 x

Since the problem asks how many years it will take for the total costs to be the same, you have to write

43700 + 1454 x = 38650 + 2078 x that is

2078 x - 1454 x = 43700 - 38650

624 x = 5050 and

x= 5050/624

x= 8,09 that is about 8 years