請大家詳細列出怎樣做，plz
更新1:
還有一題 Alan is 24 years younger than his father. Four year ago, his age was one third his father's. Find their present ages. (Set up two equations)
simultaneous linear equations
2008-10-25 6:16 am
1. David has 10 coins, some of them are $5-coins and the rest are $2-coins.The coins amount to $32 altogether, how many coins of each kind does David have?(set up two equations)
請大家詳細列出怎樣做，plz
請大家詳細列出怎樣做，plz
回答 (1)
2008-10-25 7:46 am
✔ 最佳答案
Let x and y be the number of $5-coins and $2-coins respectively.x+y = 10--------------(1)
5x+2y = 32------------(2)
From(1),
x+y = 10
x = 10-y ---------------(3)
Substitute (3) into (2) ,
5(10-y)+2y = 32
50-5y+2y = 32
3y = 18
y = 6
From (3),
x = 10-(6) = 4
Therefore , David have four $5-coins and six $2-coins.
參考: me(f.4)
收錄日期: 2021-04-19 02:08:20
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20081024000051KK01935