Question

Suppose Johnny invests $2,745 into an account, which has been earning interest for many years and he now has a total of $39,974. In two or more sentences explain why a negative number would/wouldn’t be reasonable in the solution of the rate he received on his investment.

Answer 1

A  negative  number wouldn't be for this problem because  he did invest 2,745 but he is earning that money as well. He is adding  more he is not taking away anything.

Answer 2

The amount of money went up, not down. That's why it can't be a negative number isn't reasonable.
Johnny had a smaller number to begin with than he ended up with. This means that the interest must have been positive