A photographer store sells sampler a consisting of 6 rolls of color film and 4 rolls of black and white film for $82. It also sells sampler B , consisting of 4 rolls of color film and 6 rolls of black and white film for $68. What is the cost per roll of each type of film?

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?