Question

To find simple interest, you multiply the principal (in dollars), the interest rate (as a decimal), and the time in years.

Answer 1

Here we have $400 originally and it is invested at an interest rate of 0.015 for 4 years.

Therefore we can say that the interest rate is 0.015 * 4 * 100 = 6% for the 4 years.

Simple interest is 6% / 4 = 1.5%.

And the principal is $400.