EZ car rental charges $40 dollars a day plus $0.25 per mile. Ace Rent-A-Car charges $25 dollars a day plus $0.45 per mile. What number of miles results in the same costs as one day?

Find an expression for each Rental car company's charge in one day where x = the number of miles driven.

EZ car rental: 0.25x + 40

Ace Rent-a-car: 0.4x + 25

You want to find when the two expressions are equal, so set the two expressions equal:

0.25x + 40 = 0.40x + 25

Solve for x!

0.25x + 15 = 0.40x

15 = 0.15x

x = 15/0.15

x = 100

You can check by plugging the number back in:

0.25 (100) + 40 = 65

0.4 (100) + 25 = 65