Your local radio station is having their yearly mp3 and concert ticket giveaway. for one minute, every 5th caller will win an mp3 player and every 7th caller will win concert tickets. you were just the first caller to win both an mp3 player and concert tickets! what number caller are you

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?