GMAT PREP Profit loss

Two equations

Both sold at $20,000 each

we'll let x be the purchase of 1st, y be the purchase of 2nd
1. sold for 25% profit
x + x(0.25) = 20,000
which means x * (5/4) = 20,000
x = $16,000

2. sold for 20% loss
y*(0.80) = 20,000
then y = $25,000

so the dealer spent 16,000 + 25,000 = $41,000 to buy two cars and sold for $40,000.

Which means he lost $1000.

Here another approach..

let the First car A and the second car B

Profit:
20,000 * A= 1.25 ( which is 25% profit)
A= 20,000/1.25 = 24,000 ,Therefor the profit is 24,000-20,000= 4000

Loss:
20,000 * B= 0.80 ( which is 20% loss)
B= 20,000/0.80= 25,000 , Therefor the loss for B is 20,000-25,000= -5000

Adding them = 4000-5000= -1000 Loss..