单选题 If three water pipes A, B and C are working at the same time, they can fill a swimming pool in 6 hours, if only A and B work, it needs 8 hours to fill the swimming pool, in how many hours can C fill the swimming pool alone?
【正确答案】 B
【答案解析】A、B、C三个水管一起开需要6个小时，A、B一起开需要8个小时，假设C单独工作需要C小时，那么：1/8+1/C=1/6，C=24，选择B。