The interest of 330,600.3.4 refers to the annual interest rate of 3.4%, and the interest amount = principal * interest rate * time, so the interest of 300,000 yuan is 3.4. The amount to be repaid in three years is the principal of 300,000 plus interest of 30 * 3.4% * 3 = 30,600 yuan, and the total amount to be repaid is 330,600 yuan.