问题 解答题

如今,餐馆常用一次性筷子,有人说这是浪费资源,破坏生态环境。已知用来生产一次性筷子的大树的数量(万)与加工后一次性筷子的数量(亿双)成正比例关系,且100万棵大树能加工成18亿双一次性筷子。

(1)求用来生产一次性筷子的大树的数量y(万棵)与加工后一次性筷子的数量x(亿双)的函数关系式;

(2)据统计,我国一年要耗费一次性筷子约450亿双,生产这些一次性筷子约需要多少万棵大树?每1万棵大树占地面积约为0.08平方千米,照这样计算,我国的森林面积每年因此将会减少大约多少平方千米?

答案

解:(1)设y=kx,由题意得:100=18k

求得

所以用来加工一次性筷子的大树的数量y(万棵)与加工后筷子的数量x(亿双)的函数关系示为

(2)当x = 450时,(万棵),

2500×0.08=200平方千米 。

阅读理解
The following are some advertisements(广告). Read them and answer the questions.
No. 1   A big house with a big yard for a big family. There are four bedrooms, three bathrooms, a big living room and a great kitchen.
The house costs $2,000 a month. Call Mrs. Morris at 4560987.
 
No. 2   Great location! A nice new flat building with a swimming pool. There is a big living room, a bedroom, a bathroom and a nice kitchen.
It is $1,200 a month. The phone number is 7610201. You can ask Dana for help.
 
No. 3   There is a town house for you. The first floor is for playing games, and the second floor is for living. On the second floor, there is a living room, two bedrooms, two bathrooms and a nice big kitchen. There is also a great yard behind the house for children.
It is $1,7000 a month. Please call Nathan at 4645 2436.
 
No. 4  Here is your new home! It is a big flat with three bedrooms, a living room, a dining room and a bathroom. The flat has a good parking place(停车位) but no yard.
It is $1,600 a month. Call Wilson at 533 0202.
11. Miss Green is a student, and she hasn’t much money. It’s better for her to choose _____.
A. the big house in Ad. 1   B. the flat in Ad. 2
C. the town house in Ad. 3   D. the flat in Ad. 4
12. Mr. and Mrs. Black with their son, John, want to rent(租) a house with a yard for children. Which house is suitable for them?
A. Mrs. Morris’ house   B. Wilson’s flat   C. Dana’s flat   D. Nathan’s town house.
13. The flat with a parking place costs _____.
A. $2,000   B. $1,200   C. $1,7000   D. $1,600
14. There are _______ kinds of houses in these four advertisements.
A. two   B. three   C. four   D. five
15. The advertisements tell us the information about some _______.
A. hotels   B. supermarkets   C. houses   D. restaurants
选择题