Consumer Math! Please Help! (study Guide)?

Last two questions that i have left on my study guide, please help.!

You are debating whether to buy a new computer for $1,360.00 with a discount of 10% and sales tax of 6.5% or a refurbished computer with the same equipment for $1,095.00 and sales tax of 5.75%. If a savings account earns a 3.75% APR, how much do you really save with a refurbished computer if you put the difference into the savings account for a year and calculate using the simple interest formula?

Your parents have a credit card with a balance of $3,287.90 at an interest rate of 14.5% APR. They pay $1,200.00 each month on the due date until the card is paid off. How many months does it take to pay off the card, and what is the total amount paid including interest?

Thanks

1360 * .9 * 1.065 = 1303.56

1095 * 1.0575 = 1157.96

you save
1303.56 – 1157.96 = 145.60

A = P(1 + rt)
A = 145.6 * 1.0375
A = $151.06

PMT = Pv(r/n) / [1 - (1 + r/n)^(-nt)]

1200 = 3287.9(.145/12) / [1 - (1 + .145/12)^(-12t)]
1 – (1 + .145/12)^(-12t) = 476.7455 / 14400
-[12.145) / 12]^-12t = -13923.2545 / 14400
[12.145) / 12]^-12t = 13923.2545 / 14400
t = ln (13923.2545 / 14400) / ln (12.145 / 12)^-12

t = 0.23359159326750163106485009310638 years
t = 2.803 months