Independent solution

How to solve this Loan Balances and Amortization question

Setup

Setup

Express total interest under the 20-year lump-sum repayment.

IL=X[(1.05)201]I_L=X[(1.05)^{20}-1]

Model

Model

For ten level payments, total interest is total payments minus principal.

IA=10Xa100.05XI_A=10\frac{X}{a_{\overline{10}|0.05}}-X

Compute

Compute

Set the lump-sum interest 1,000 above the level-payment interest and solve X = 736.2404.

ILIA=1000I_L-I_A=1000
X=736.24042723X=736.24042723

Answer

Answer

The borrowed amount is approximately 736, selecting choice D.

X736(D)\boxed{X\approx736\quad\text{(D)}}