A pencil and eraser together cost 55 cents. The pencil costs 50 cents more than the eraser. How much does the eraser costs

The answer is 5 cents. To get this answer you subtract the cost of the pencil from the total cost, and that gives you the price of the eraser.

55 (total cost) - 50 (cost of pencil) =.05 cents (cost of eraser)