Charlie took out a car loan for $13,000 at 3% simple interest.

a.) How much interest will he pay after 6 years?

b.) Suppose he pays off the loan in 4 years instead of 6 years. How much

money will he save in interest?

2,340 is the answer for the first ... and the second ... 1.560. All you have to do is divide / ...

What you are missing is a simple formula: I=PRT. Means Interest (in dollars, not %) = Principal (downpayment or original savings) X Rate (percentage rate as a decimal: 5% = 0.05) X Time (in years - convert months into decimal part of 1 year). You can also change that formula around. For example, to find Time, divide Interest by Principal X Rate (T = I / PR).

To get you started, here's #1 in your problem list: I = PRT. I = $500 * 0.06 * 0.25 (0.06 = 6% and 0.25 = 3 months of 1 year). Multiply it out: I = $7.50. Now you can do the rest!