问题 解答题

某厂准备生产甲、乙两种适销产品,每件销售收入分别为3千元,2千元.甲、乙产品都需要在A,B两种设备上加工,在每台A,B上加工一件甲产品所需工时分别为1小时、2小时,加工一件乙产品所需工时分别为2小时、1小时,A、B两种设备每月有效使用台时数分别为400小时和500小时.如何安排生产可使月收入最大?

答案

设甲、乙两种产品月的产量分别为x,y件,

约束条件是 

x+2y≤400
2x+y≤500
x≥0
y≥0

目标函数是z=0.3x+0.2y

由约束条件画出可行域,如图所示的阴影部分

由z=0.3x+0.2y可得5z为直线z=0.3x+0.2y在y轴上的截距,截距最大时z最大.

结合图象可知,z=0.3x+0.2y在A处取得最大值

2x+y=500
x+2y=400
可得A(200,100),此时z=80万

故安排生产甲、乙两种产品月的产量分别为200,100件可使月收入最大.

单项选择题 A1/A2型题
阅读理解

根据短文内容,从短文后的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.   

     Taking good notes is a time-saving skill that will help you to become a better student in several ways. 

   1_  Second,your notes are excellent materials to refer to when you are studying for a test. Third ,

note-taking offers  variety to your study time and helps you to hold your interest.

     You will want to take notes during classroom discussions and while reading a textbook or doing

research for a report. _ 2_  Whenever or however you take notes, keep in mind that note-taking is a

selective process.  _ 3__  The following methods may work best for you.     

      ·Read the text quickly to find the main facts and ideas in it.

      ·Carefully read the text and watch for words that can

show main points and supporting facts.

      ·Write your notes in your own words.

      ·   4_   

      ·Note any questions or ideas you may have about what is said or written.

      As you take notes, you may want to use your own shorthand (速记). When  you  do, be  sure  that  

you understand your symbols and that you use them all the time. __5__    

A. Use words , not complete sentences.

B. There are three practical note-taking methods.

C. You must write your notes on separate paper.

D. Otherwise,you may not be able to read your notes later.

E. You will also want to develop your own method for taking notes.

F. That means you must first decide what is important enough to include in your notes.

C. First, the simple act of writing something down makes it easier for you to understand and remember it.