Money Interest Problem 
Jake has loaned 20000 pesos from the bank with an interest of 10% every year. If Jake completes the payment within 3 years, what amount should be paid to the bank?

Could someone explain to me the entire solution?

Amount= $Principal+Interest$
(assumption, Interest is calculated at initial principal, i.e. simple interest)
$Interest$=$Principal\times Rate\times years$
=$20,000\times0.1\times 3$
Total money= $20,000+6,000$
