A new car is purchased for \$20,000$20,000 and over time its value depreciates by one half every 6.5 years. How long, to the nearest tenth of a year, would it take for the value of the car to be \$9,000$9,000?

Asales representative from a local radio station is trying to convince the owner of a small fitness club to advertise on her station. the representative says that if the owner begins advertising on the station today, the club's total number of members will grow exponentially each month. she uses the given expression to model the number of club members, in hundreds, after advertising for t months.