Ace Car Rental rents cars for x dollars per day plus y dollars for each mile driven. Carlos rented a car for 4 days, drove it 160 miles, and spent $120. Write an equation to represent Carlos’s expenses. Use "x" to reresent the number of days and "y" to respresent the number of miles.

Let's break down the given information:

Ace Car Rental rents cars for x dollars per day.
Carlos rented a car for 4 days, so he paid 4x dollars for the rental period.

Ace Car Rental charges y dollars for each mile driven.
Carlos drove the car for 160 miles, so he paid 160y dollars for the mileage.

Carlos spent a total of $120, so we can write the equation:

4x + 160y = 120