-knowledge of buying drinks

Students, when you are holding a popsicle in your left hand and a bottle of drink in your right hand on a hot summer day, have you ever thought that this is also related to mathematics?

Please listen to me tell a short story.

One day in the summer vacation, three friends, Xiaohua, Kobayashi and Xiaojun, from Building 3 of Xincheng Garden, went to buy the same brand of drinks, with two specifications: large bottles and small bottles. Xiaohua wants to buy 15 bottles, Kobayashi wants to buy 10 bottles, and Xiaojun wants to buy 2 large bottles and 4 small bottles. They all had this drink in three shopping malls not far from where they live.

These three friends used to like to use their brains. Now, they want to buy drinks, and they buy them cheaply. So, three people launched an investigation.

They got the following information in three shopping malls:

Large drinks per bottle 10 yuan, small drinks per bottle 2 yuan.

Sales method of a shopping mall: buy 1 send large bottles 1 small bottles.

Sales method of Mall B: 10% discount for the whole audience.

Sales method of Mall C: 20% discount in 30 yuan.

Xiaohua calculated that 30 yuan was needed to buy 15 vials, and 24 yuan was needed to go to C mall, so he decided to buy them in C mall.

Kobayashi calculated that 20 yuan was needed to buy a 10 vial, but 2 yuan was cheaper to go to mall B, so he decided to go to mall C. 。

Xiaojun calculated that it takes 28 yuan to buy two large bottles and four small bottles, but it's cheaper to go to 4 yuan, a shopping mall, so he decided to buy it at C shopping mall.

In this way, the three of them bought drinks and went home happily

How do you feel after listening to my little story? You can think about something with me: there are cheaper ways to buy. Don't worry, let me tell you slowly.

Xiaojun can get 4 yuan cheaper in shopping mall A, but if he buys the remaining two vials in shopping mall B, he can get 0.4 yuan cheaper. If he buys two more vials, with a total price of more than 30 yuan, he only needs 24 yuan in the mall C, which is more cost-effective.

Also, if all of them go to C mall together, it means that all the drinks bought by three people will be 20% off, so Kobayashi and Xiaojun will get more benefits.

I don't have to tell you how to calculate it.

How's it going? How interesting! In life, mathematics is always extending a warm hand to you. As long as you hold her hand tightly, you will become smarter and smarter.

(Comments: For the practical problems encountered in such life, most students think that three people will buy it cheaply by themselves, but the author of this article thinks that it will be cheaper if three people buy it together. )