钟表的时针与分针在运行过程中每隔一定时间就相遇一次，相遇间隔的时间是（　　）

下列说法正确的是（     ）

某旅行社组织一批游客外出旅游，原计划租用45座客车若干辆，但有15人没有座位；若租用同样数量的60座客车，则多出一辆车，且其余客车恰好坐满．已知45座客车租金为每辆220元，60座客车租金为每辆300元，问：

（1）这批游客的人数是多少？原计划租用多少辆45座客车？

（2）若租用同一种车，要使每位游客都有座位，应该怎样租用才合算？

    Everybody needs water. Everything needs water. We use water to wash the bowls(碗), clothes and ourselves. We use water to plant trees, flowers and crops(庄稼). Where does all water come from? It comes from clouds.

    Some of rain goes into the ground. Many people get it under the ground. Some rain water goes into the hills. It runs into lakes and rivers. Many people get it there.