The interest rate is 5.4%, that is, the monthly interest rate is 5.4%/ 12.

Monthly repayment 168000 20 years (240 months):

168000 * 5.4%/ 12 * ( 1+5.4%/ 12) 240/[( 1+5.4%/ 12) 240-]

Total interest:1146.18 * 240-168000 =107083.2 yuan.

Description: 240 is the power of 240.