Question 13241
Chelsea made a total of 12,000 dollars in sales (6,000 + 6,000)
For car 1, note he made 20% profit. So the price, call it x, was the price Chelsea paid for the car in the beginning. We have 6000 = x + x(.20).  We can factor out an x on the right hand side of this equation to get 6000 = x(1 + .20).  So to solve for x (the price Chelsea paid for car 1) divide 6000 by 1.20 to get x = 5,000.

For car 2, note he lost 20% on the car.  Let y be the price Chelsea paid for car 2.  Then 6,000 = y - y(.20).  Factoring out a y on each side yields 6000 = y(1-.20) or 6,000 = y(.80).  To solve for y we divide 6,000 by .80 to get $7,500. 

So the total price Chelsea paid for the cars was x + y = $5,000 + $7,500 = $12,500.  However he only sold the cars for $6,000 each and gained a total of $12,000.  So, in the long run, Chelsea actually lost $500.