13) Mark John bought an item in a department store subject for 10% discount and another 20% after the first discount. How much should he pay for the item that is originally marked P200?

14) Mrs. Abad sells used laptops. Her commission for every laptop sold is 15%. If her total sales reached P44 960, how much was her commission?

15) Mrs. Salcedo borrowed the amount of P250 000 from a lending institution to start up a business. If she agrees to pay the amount after three years on a 12.5% simple interest per year, how much will she pay after three years?​