mr. kork sold his car for 8,400. this was 200 more than two fifths of what he had paid for the car originally

If your question is, "how much had Mr. Kork paid for the car?"

(8,400-200) /.4=$20,500

Achristensen's answer is correct. Just want to add a little more explanation how to arrive at the result.

let x be the original price.

Rewrite the verbal question as an equation using x:

8400 = 200 + 2/5 * x

solve for x:

8400-200 = 2/5*x

5/2*8200 = x

x = 20500

The original price was $20,500