Reginald is selling apples. He sells each apple for $1.25. He plans to use his profits to help repair his bike. His bike cost $80 and the repairs cost 25% of what his bike cost. After the repairs are paid for, 1/5 of the money he'd earned remains. How many apples did he sell?
Let’s work this out in a step by step way to be sure we have the right answer.
20
The bike repairs cost $20 because 80 x.

25 = 20.

Call the amount he earns e.

We know that e - 20 = 1 / 5e.

Therefore 5e - 100 = e.

Therefore, 4e = 100.

Therefore, e = 25.

Therefore, he sold 20 apples because 25 / 1.

25 = 20.

.

So, the final answer is 20