Under compound interest, not only does the principal generate interest, so does the previous accumulated interest. The future value F of P dollars compounded annually for t years with an annual percentage rate (APR) r expressed as a decimal is .
1.5 because is 2 inches is 20 bags the it be 1 inch for 10 bags, so going half of 10 is 5 and 1 divided by 2 is .5... so add up the 10 bags and 5 bags to get an answer of 1.5 inches.
