选择题
2004 AMC 8 Problem 12: Cell Phone Battery
Niki usually leaves her cell phone on. If her cell phone is on but she is not actually using it, the battery will last for 24 hours. If she is using it constantly, the battery will last for only 3 hours. Since the last recharge, her phone has been on 9 hours, and during that time she has used it for 60 minutes. If she does not use it any more but leaves the phone on, how many more hours will the battery last?
A.
7
B.
8
C.
11
D.
14
E.
15