问题 解答题

刘老师装饰厨房需用 480 块某品牌的同一种规格的瓷砖,我市盛世商贸城装饰材料商场出售的这种瓷砖有大、小两种包装,大包装每包50片,价格为30元;小包装每包30片,价格为20元,若大、小包装均不拆开零售,请你帮助刘老师制定一种购买方案,使购买瓷砖所付费用最少.

答案

设购买大包装x包,小包装y包,

根据题意,得50x+30y=480.                      

因为x、y为非负整数,所以方程的解为

x=0 
y=16
或 
x=3
y=11
x=6
y=6
x=9
y=1

当x=0,y=16时,所付费用为:0×30+16×20=320(元);

当x=3,y=11时,所付费用为:3×30+11×20=310(元);

当x=6,y=6时,所付费用为:6×30+6×20=300(元);

当x=9,y=1 时,所付费用为:9×30+1×20=290(元).

所以购买大包装9包,小包装1包所付费用最少,费用为290元.

完形填空
When I was in the sixth grade, one day my teacher asked our class to think about the question “What does ‘doing the right thing’ mean to you?” over the weekend. We could talk to our parents or anyone else we thought might have a good answer.  1  Monday, we were to hand in an essay(论文) on it, and be prepared to live up to our  2 .        
The entire weekend, I was trying to  3  something that would impress my teacher and be easy to live by. I talked to my parents, called my grandmother and asked my neighbor. Everyone had good answers, but I didn’t feel like I could live up to them.
On Sunday afternoon, my parents said they were going to my Aunt Cindy’s house. That usually 4  that I would have to entertain my four-year-old cousin Andrea  5  my parents visited. I found a Disney movie for Andrea, and then I sat down and started to write my essay. It was due(到期的)the next morning and this was my last  6  .
Soon I felt a pair of eyes on me. It was Andrea.  “What are you doing?” Andrea asked. “I have to write an essay about what ‘doing the right thing’ means to me.” I answered. Andrea laughed. Could this smart four-year-old know the answer?  “That’s easy,” she said. “Doing the right thing means being nice to your family and friends. Never lie. Eat lots of fruits and vegetables. Take a bath when you’re 8 . And never put rocks in your mouth.”
I stared with great  9  at my little cousin. Then I jumped up and gave her the biggest hug. Not only had Andrea answered a very tough question for me, but I could easily live by  10  of her answers. All I had to do was to be nice, not to lie, to keep myself clean and healthy, and never put rocks in my mouth. So when I wrote my essay, I  11  the story about Andrea and how she had answered my question.
Two weeks later, my teacher returned everyone’s essays. I  12  an A+ along with a little note my teacher had written at the top: “Always do the right thing and give Andrea an A+, too!”
小题1:
A.By B.OverC.AboutD.For
小题2:
A.answers B.plansC.adviceD.information
小题3:
A.look throughB.keep onC.make up ofD.come up with
小题4:
A.leftB.meantC.decidedD.explained
小题5:
A.sinceB.becauseC.whileD.before
小题6:
A.taskB.chanceC.step D.choice
小题7:
A.quicklyB.normallyC.seriouslyD.possibly
小题8:
A.dirtyB.tiredC.sleepyD.unhappy
小题9:
A.prideB.fearC.surpriseD.worry
小题10:
A.anyB.allC.someD.none
小题11:
A.readB.foundC.includedD.returned
小题12:
A.preparedB.expectedC.introducedD.received
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