Mr. Crab borrowed P25,300 for 3 years at an interest rate of 8% per year. The problem asks to calculate the amount of interest charged. The second problem asks to calculate the time period, in years, that P25,000 would need to be invested at 10.75% interest to earn P8,200 in interest. The third problem provides an investment of P50,000 that earned P10,062.50 in interest over 1 year and 9 months and asks to calculate the interest rate. The final problem asks to calculate the interest earnings after 3 years and 2 months on an initial investment of P18,300 at an interest rate of 9.75%.