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 would not be reasonable in the solution of rate he received on his investment. So we cannot have a negative rate received on the investment if the final amount is more than we started off with. 

The reason being, when you have a positive percent rate of a number, you take that percent of the number and add it to the original. For example:

10% interest of $100 would give you $110

Now if that 10% were a -10% then you would be adding a negative number to the original. So:

-10% of 100 would give us $90 because 10% of 100 is 10 then you change it to a -10 and add -10+100=90

So we cannot have a negative rate received on the investment if the final amount is more than we started off with.

(The answer is bold) Hope this helps!