According to the formula: loan amount = monthly repayment amount * 1-( 1+ monthly interest rate)-repayment months/monthly interest rate.

36000 =1335.98 *1-(1+monthly interest rate) -36/ monthly interest rate

Monthly interest rate = 1.65799%? ; Annual interest rate = 19.89589%

(two) the forty-second stage:

According to the formula: loan amount = monthly repayment amount * 1-( 1+ monthly interest rate)-repayment months/monthly interest rate.

36000 =1196.75 *1-(1+monthly interest rate) -42/ monthly interest rate.

Monthly interest rate = 1.65799%? ; Annual interest rate = 19.89589%? ?

(3) 48,000 yuan? Situation:

According to the formula: loan amount = monthly repayment amount * 1-( 1+ monthly interest rate)-repayment months/monthly interest rate.

48000 =1800 *1-(1+monthly interest rate) -36/ monthly interest rate

Monthly interest rate = 1.72 155%? ; Annual interest rate =20.65859%? ?

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The interest rates of the first two methods are the same; ? Finally, the interest rate is slightly higher.