您好
1.
假设当前每期还款额为A:
300000=A×(P/A,3%,10),A=300000/8.5302=35169.16(元)
2.
假设提前偿还借款之后的每期还款额为B:
300000=35169.16×(P/A,3%,4)+60000×(P/F,3%,4)+B×(P/A,3%,6)×(P/F,3%,4)
B=[300000-35169.16×(P/A,3%,4)-60000×(P/F,3%,4)]/[(P/A,3%,6)×(P/F,3%,4)]
=115962.7154/(5.4172×0.8885)
=24092.73(元)
您理解一下。