A car dealership sells used cars for$7,000 and new cars for$1,600. If a total of 17 cars were sold for $191,000. How many of the cars sold were used?

Let x be the number of used cars; y be the number of new cars. Since there are two unknowns, we have to formulate two independent equations to be able to solve the problem. Although, I think that would be 16,000, and not 1,600. It is only logical that new cars are more expensive than used cars.

(1) x + y = 17

(2) 7000x + 16000y = 191000

Solving these equations simultaneously:

x = 17 - y (1)

7000x + 16000y = 191000 (2)

7000 (17-y) + 16000y = 191000

y = 8 new cars

Then, substituting this to equation 1,

x = 17 - 8 = 9 used cars