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？

    We are all learning English, but how can we learn English well? A student can know a lot about English, but maybe(可能) he can't speak English. If you want to know how to (如何) swim, you must get into the river. And if you want to be a football player, you must play football.
So, you see. You can learn English only by(通过) using(使用)it. You must listen to your teacher in class. You must read your lessons every day. You must speak English to your classmates and also you must write something sometimes. Then one day, you may find your English very good.

$\left(\sqrt{2}+\sqrt{3}-\sqrt{6}\right)\left(\sqrt{2}-\sqrt{3}+\sqrt{6}\right)$