Answer:
5,600 dollars he sold it for
Explanation:
Basically if you cross multiply, you'll do 4,000 times 40. Then divide what you get from multiplying by 100, so do 160,000 divided by 100 in this case. Then when you get that 1,600, it isn't the final step. Lastly, you'll have to add 1,600 on to 4,000 to get the markup selling price. :)