Question

Craig bought a second hand-hand bicycle for $80 and after repairing it sold it for $110. What is his profit as a percentage of the cost?

Answer 1

profit=(110-80)/80=37.5%

Answer 2

yes, the profit is 110-80 which is 30.
Now what percentage of 80 is 30?
That gives 30/80 * 100 = 37.5%