Funtions

[Guest]

I was wondering if someone can help me on my math questions? I am struggling

1. determine the interest rate on a loan of \$5400 if interest is compounded monthly for 72 months and finals of loan is \$6965.35.

list the values you used for present values, future values, number of years and numbers of compounding periods per year.

2. determine the monthly payment of a lease of \$21 568 if the interest rate is 4.8% compounded monthly for 48 months

3. over a five-year period, the maintenance on a car included two oil changes per year (\$48 each), new brakes (\$452), new tires(\$678) and a new set of spark plugs ($145). what is the average yearly maintenance fee on the car for the five-year period?

anything will be deeply appreciated

[Guest]

Do you know anything at all about "compound interest"?
https://www.investopedia.com/terms/c/co ... terest.asp

[HallsofIvy]

If annual interest rate "r" is charged on amount "A", compounded monthly, then the interest for the first month is rA/12 and the amount owed is now A+ rA/12= (1+ r/12)A. The interest for the second month is r(1+ r/12)A/12= (r/12+ (r/12)^2)A and the amount owed is now A+ (r/12+ (r/12)^2)A= (1+ (r/12)+ (r/12)^2)A. The interest for the third month is r(1+ (r/12)+ (r/12)^2)A/12= (r/12+ (r/12)^2+ (r/12)^3)A and the amount owed now is A+ (r/12+ (r/12)^2+ (r/12)^3)A= (1+ (r/12)+ (r/12)^2+ (r/12)^3)A.

Get the idea? The amount owed after n months will be (1+ (r/12)+ (r/12)^2+...+ (r/12)^n)A.