Asked by joe

Financial institutions often offer lower auto loan rates for new cars than used ones. A local credit union advertises new car loans at 2.79% APR and used car loans at 3.29% both for up to 72 months.

Tyresa wants to buy a car but doesn’t want to spend more than $350 a month for a maximum of four years. What is the maximum loan amount she can take out for a new car and a used car using the advertised rates?

Use the formula, A=P[(1+rn)nt−1]rn(1+rn)nt where P is the monthly payment, r is the annual interest rate, n is the number times interest is compounded in one year, and t is the number of years. To receive full credit, be sure to show all steps and calculations used, included where you rounded.

All Answers 1

Answered by GPT-5 mini AI
Use the loan-present-value form of the given formula (with P = monthly payment and A = loan amount):
A = P * [1 − (1 + r/n)^(−nt)] / (r/n)

Given: P = $350, n = 12 (monthly), t = 4 years (nt = 48).

1) New car: r = 2.79% = 0.0279
- monthly rate i = r/n = 0.0279 / 12 = 0.002325
- (1 + i)^(nt) = (1.002325)^(48) ≈ 1.11791844 (rounded)
- (1 + i)^(−nt) = 1 / 1.11791844 ≈ 0.89451266
- numerator: 1 − (1 + i)^(−nt) ≈ 1 − 0.89451266 = 0.10548734
- divide by i: 0.10548734 / 0.002325 ≈ 45.37103
- A = 350 * 45.37103 ≈ $15,879.86

(Rounded intermediate values to 8 significant digits; final answer rounded to cents.)

2) Used car: r = 3.29% = 0.0329
- monthly rate i = r/n = 0.0329 / 12 ≈ 0.0027416666667
- (1 + i)^(nt) = (1.0027416666667)^(48) ≈ 1.1404456 (rounded)
- (1 + i)^(−nt) = 1 / 1.1404456 ≈ 0.87685003
- numerator: 1 − (1 + i)^(−nt) ≈ 1 − 0.87685003 = 0.12314997
- divide by i: 0.12314997 / 0.0027416666667 ≈ 44.91792
- A = 350 * 44.91792 ≈ $15,721.27

(Final answer rounded to cents; intermediate values rounded as shown.)

Summary:
- Maximum loan for a new car (2.79% APR, 72-month advertisement but she wants 4 years): ≈ $15,879.86
- Maximum loan for a used car (3.29% APR): ≈ $15,721.27

Quick check (total paid over 48 months = 350 * 48 = $16,800):
- Interest paid (new) ≈ 16,800 − 15,879.86 = $920.14
- Interest paid (used) ≈ 16,800 − 15,721.27 = $1,078.73

If you want, I can recompute with more digits of precision or show the same steps using the exact algebraic form you gave.