My mother will deposit 10000 yuan in the bank for three years. After maturity, she will get back the principal and after tax interest of 10777.6 yuan from the bank. What's the annual interest rate of the three-year fixed deposit (20% interest tax)

My mother will deposit 10000 yuan in the bank for three years. After maturity, she will get back the principal and after tax interest of 10777.6 yuan from the bank. What's the annual interest rate of the three-year fixed deposit (20% interest tax)

If the annual interest rate of 3-year fixed deposit is x, then:
10000×X×3×（1－20％）＝ 10777.6 － 10000
X ＝ 3.24％
That is, the annual interest rate of 3-year fixed deposit is 3.24%

My mother deposits 10000 yuan in the bank, fixed for one year, with an annual interest rate of 4.14%. After the maturity, my mother comes to withdraw the money. How much interest should the bank pay?

10000 * 4.14% = 414 yuan

Mother deposited 10000 yuan in the bank, fixed for two years, the annual interest rate is 4.10%, exempt from interest tax?

Retrieval = 10000 × (1 + 4.1% × 2) = 10820 yuan
Do not understand can ask, help please adopt, thank you!