finite math
posted by Amber .
The price of a new car is $16,000. Assume that an individual makes a down payment of 25% toward the purchase of the car and secures financing for the balance at the rate of 6%/year compounded monthly. (Round your answers to the nearest cent.)
What monthly payment will she be required to make if the car is financed over a period of 48 mo? Over a period of 72 mo?
What will the interest charges be if she elects the 48mo plan? The 72mo plan?

$12,000 loan amount
r = .06/12 = .005
n = 48 or 72
1+r = 1.005
(1+r)^n = .7871 for n = 48
1  (1+r)^n = .2129 for n = 48
payment = loan [ r/(1 (1+r)^n ) ]
payment for 48 months = 12,000[.005/.2129]
=$281.82
now you do the 72 months 
i got $198.87
what about the interest charges? 
LOL
well
12,000/48 = 250 per month with no interest.
you paid 281.82 including the interest at 6% compounded monthly 
(281.82250)*48?

right

Determine the simple interest rate at which will grow to in the months. Round your answer to the nearest tenth of percent