题干

铁路部门规定旅客免费携带行李箱的长、宽、高之和不超过160cm,某厂家生产符合该规定的行李箱,已知行李箱的高为30cm,长与宽的比为3:2,则该行李箱的长的最大值为多少厘米?
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答案(点此获取答案解析)

解:设长为3x,宽为2x,

由题意,得:5x+30≤160,

解得:x≤24,

故行李箱的长的最大值为:3x=72,

答:行李箱的长的最大值为72厘米

同类题4

根据短文内容,从短文后的七个选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

    Many parents would like to teach their children English at home, but don't know how to start. It doesn't matter if your own English is not perfect. The most important thing is that you give your children lots of encouragement and praise.____ They will need some time to learn the language.

Make it a rule

    Try to do certain activities at the same time every day.____ For example, you could read an English story with your children before bedtime. Repetition (重复) is important — children often need to hear words many times before they say them themselves.

Playing games

    ____ Cards are a great way to teach words and there are many different games which you can play with cards, such as Memory and Happy Families.

Using everyday situations

    The advantage of teaching English at home is that you can use everyday situations to practice the language naturally. For example:

    Talk about clothes when your child is getting dressed ("Let's put on your blue socks", etc.).

    ____When you go to the supermarket, give your child a list of things to find.

    Using songs

    Songs are a really good way to learn new words. Songs with actions are especially good for very young children because they are able to join in.____

A. Fifteen minutes is enough for very young children.

B. Children learn naturally when they are having fun.

C. Teach food words when you are cooking or going shopping.

D. The actions often show the meaning of the words in the song.

E. With younger children, there is no need to teach grammar rules.

F. Don't worry if your child doesn't start speaking English immediately.

G. Children feel more comfortable and confident when they know what to expect.