Forty students bought caps at the baseball game. Plain caps cost $4 each and deluxe ones cost $6 each. If the total bill was $236, how many students bought the deluxe cap?

38

Step-by-step explanation:

If all had bought the plain cap, the bill would be $4*40 = $160. The bill is $76 more than that.

Each deluxe cap purchased adds $2 to the total bill (above the cost of a plain cap), so there must have been $76/$2 = 38 deluxe caps purchased.