Dave drives to work each morning at about the same time. His commute time is normally distributed with a mean of 47 minutes and a standard deviation of 5 minutes. What percentage of time is his commute less than 52 minutes?

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?