上了一上午的课，终于盼到了中午吃饭的时间了。大家七嘴八舌你一言我一语地讨论中午吃什么。有的人说：“吃食堂盖饭！”，有的人说：“吃戎城人家！”最后宿舍长大人一拍桌子：“大家叫外卖！”于是同学们饥肠辘辘地打电话叫外卖。按饭馆的规定，送餐费按如下方式进行计算：

每单少于20元（不含）不予以送餐服务；

每单在20元（含）至30元（不含）间将收取8元送餐费；

每单在30（含）至40元（不含）间将收取5元送餐费；

每单在40元（含）以上将不收取送餐费。

请你计算这顿午餐的全部费用。-



On a morning class, and finally looked forward to the time to eat at noon. You rhetoric to talk about what I eat at noon. Some people say:　eat canteens to cover rice! , Some people say:　eat Rongcheng people!　Finally, a grown-up hostel pound the table:　We called take-away!　So the students hungry call to take-away. According to the provisions of the restaurant, meals are calculated as follows:

　Less than 20 yuan per single (excluding) not to room service

　Each single in 20 yuan (inclusive) to 30 yuan (excluding) will be charged between 8 yuan meals

　Each　30 (inclusive) to 40 (excluding) will be charged between 5 yuan meal delivery

　Each single in the 40 yuan (inclusive) or more will not charge meal delivery.

　Please calculate the full cost of the lunch.