future amount

Problem
By the conditions of a will, the sum of P2.5M is left to a girl to be held in a trust fund by her guardian until it amounts to P4.5M. When will the girl receive the money if the fund is invested at 8% compounded quarterly?

In compound interest, the interest earned by the principal at the end of each interest period (compounding period) is added to the principal. The sum (principal + interest) will earn another interest in the next compounding period.
 

Consider \$1000 invested in an account of 10% per year for 3 years. The figures below shows the contrast between simple interest and compound interest.