Suppose johnny invests $41,745 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 of the investment.

Well, the interest literally mean the amount that add up to your previous capital that you invest in the past.
If you invest an amount of money and get an interest revenue out of it, the amount of your capital will be increased , not decreased

It would not be reasonable, presuming he had a positive interest rate. When you have an investment, the purpose is to increase your total money. There is a possibility that it was a poor investment, and he made a loss, however this is not likely or reasonable.