Pay the handling fee for each installment, which is equivalent to the monthly repayment of principal and interest. The calculation is as follows:

Annual interest rate = rate (24, 1/24 * (1+7.89%),-1) *12 = 7.4001%.

Second, the installment amount

Suppose 12000 yuan is divided into 24 periods, and the calculation is as follows.

Total handling fee = 12000*7.89%=946.8.

Monthly repayment amount = (12000+946.8)/24 = 539.45

Third, check the annual interest rate.

The annual interest rate is 7.400 1%, and it will be paid back to 12000 yuan in April.

Monthly repayment amount =12000 * 7.4001%12/(1+7.4001%12).

Note: (1+7.4001%12)-24 is the reciprocal of (1+7.4001%12) 24. 24 is the 24th power.