1. A designer is going to spend $5 400 000 on the renovation of a hostel to provide accommodation for at least 130 people.Given that the number of single rooms should be less than that of the double rooms, and the renovation fee for each room is $36 000. Write down all the constraints about the number of single rooms and the number of double rooms.
2. Gary is going to prepare two brands of flour, A and B, with 10kg of grade I flour and 24kg of grade II flour. Brand A is formed by mixing grade I flour and grade II flour in the ration of 2:3, while brand B flour is formed by mixing grade I flour and grade II flour in the ratio of 1:4. Given that at least 2kg of brand A flour should be prepared, and the amount of brand A flour prepared should not be more then 1/3 of the brand B flour prepared. Write down all the constraints about the amount of brand A flour and brand B flour to be prepared.
Are there any advice on how to tackle such questions on "writing constraints"?
Thank you very much!
急！Maths Linear Programming（2條）
2011-08-13 7:14 am
回答 (1)
2011-08-13 6:29 pm
✔ 最佳答案
You should draw a table to tackle such questions concerning linear programming. Take Q1 as an example.Let x be no. of "single roon" and let y be no. of "double room"(Please take out a paper)imagine there is a chart with 12 boxes.now please draw the box like what I have done.(-) money spent($) Capacity
single (x) 36000x 1x
double (y) 36000y2y
(-) <(or equals)5400000 >(or equals to)130
Why 36000x and 36000y?
This is because the question has given that each room need $36000 to renovate,
if you have x (single) room, you must have paid $36000x to renovate single room. Same as double room.
Also, you only have 5400000 to do the whole thing, so the total amount of money needed (36000x + 36000y) < 5400000For Capacity,
Certainly, single room can only accommodate 1 person
Double room can accommodate 2 people.
If there are x single room,
They can totally accommodate (1)x people
Same for double room.
Given that at least 130 people can be accomodate,
1x + 2y >(equal to 130)Lastly, the question has given that x(no. of sing. room) < y (no. of double room)note that x and y are non-negative integers, because there should not be neagative no. of rooms (e.g. -100 rooms?), and there should not be like 1.1 rooms. So,
Required constraints:
(36000x + 36000y) <(=) 5400000
x+2y >(=) 130
x
x and y are non-negative integers
2011-08-13 10:30:39 補充：
Required constraints:
(36000x + 36000y) <(=) 5400000
x+2y >(=) 130
x
2011-08-13 10:31:04 補充：
I'm sorry. The third one should be x
2011-08-13 10:31:18 補充：
=.= x (smaller than )y
參考: F.6 student
收錄日期: 2021-04-16 13:10:54
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20110812000051KK01360