Robert invests $1,100 at an annual interest rate of 8% for the period of 1 year. what equation shows the relationship between principal amount (p), rate of interest (r), period of investment in years (t), and interest earned (i).

You just purchased two coins at a price of $670 each. because one of the coins is more collectible, you believe that its value will increase at a rate of 7.1 percent per year, while you believe the second coin will only increase at 6.5 percent per year. if you are correct, how much more will the first coin be worth in 15 years?