After spending many hours studying for your math class, you decide to reward yourself with a case of cream soda. Unfortunately, Corner Market only had a warm case left. You buy several bags of ice and decide to chill it at home. When you get home, the temperature of the soda is 76° F, and you proceed to pack it in ice. After 10 minutes, the temperature cooled to 70° F. If cream soda is best served at 60° F or cooler, how much longer must you wait to enjoy your chilled cream soda?