1. Calculate a loan of 280,000 yuan. When the interest rate is 0.4% in that year, what is the total interest of 10? Assume that the total loan amount is P (principal), the annual interest rate is R, the number of loan years is N, and the calculation formula of total interest I is: I = P× R× N.
2. According to the subject conditions, P = 280,000, the annual interest rate is 0.4% (decimal 0.004), and the loan term is 10 year, which is substituted into the formula for calculation.
The calculation result is: 1 1200 yuan. So the total interest of 10 year is 1 1200 yuan.