Amount Lucy will be paying in interest will be $38,596.2
Using the compound amount formula to get the amount after she will pay back after 20 years expressed as:
[tex]A =P(1+\frac{r}{n} )^{nt}[/tex]
Substitute the parameters into the formula;
[tex]A=73,250(1+\frac{0.0315}{12} )^{20(12)}\\A= $73,250 (1.8761)\\A= \$137,421.49[/tex]
If Excel calculates the monthly payment to be $411.77, the amount paid for 20 years will be $411.77 * 240months = $98,824.8
Amount Lucy will be paying interest will be $137,421- $98,824.8 = $38,596.2
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