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教育王國 討論區 初中教育 求式呀! 唔該!
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求式呀! 唔該! [複製鏈接]

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761
1#
發表於 08-3-18 11:44 |只看該作者 |倒序瀏覽 |打印
There are a total of 30$50-cent coins and $2-coins in a moneybox, and the total value of the coins is $42. How many coins of each denomination are there in the moneybox? (use linear equations )
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12288
2#
發表於 08-3-18 11:54 |只看該作者
原文章由 crystalwesley 於 08-3-18 11:44 發表
There are a total of 30$50-cent coins and $2-coins in a moneybox, and the total value of the coins is $42. How many coins of each denomination are there in the moneybox? (use linear equations ):questi ...


Let X be the quantity of $50cents coins, and Y be the quanity of $2 coins

X + Y = 30

0.5X + 2Y = 42

you need to try to solve the equation by yourself, otherwise you cannot improve your mathematics

Rank: 9Rank: 9Rank: 9


20633
3#
發表於 08-3-18 12:09 |只看該作者
長老 ,

原文章由 布甸仔媽媽 於 08-3-18 11:54 發表


Let X be the quantity of $50cents coins, and Y be the quanity of $2 coins

X + Y = 30

0.5X + 2Y = 42

you need to try to solve the equation by yourself, otherwise you cannot improve your mathematic ...

Rank: 6Rank: 6


6260
4#
發表於 08-3-18 14:24 |只看該作者
長老真係寶刀未老!


原文章由 布甸仔媽媽 於 08-3-18 11:54 發表


Let X be the quantity of $50cents coins, and Y be the quanity of $2 coins

X + Y = 30

0.5X + 2Y = 42

you need to try to solve the equation by yourself, otherwise you cannot improve your mathematic ...
[img align=right]http://xs511.xs.to/xs511/07021/dance009d23t.gif[/img]

Rank: 7Rank: 7Rank: 7


12810
5#
發表於 08-3-18 15:33 |只看該作者
長老



原文章由 布甸仔媽媽 於 08-3-18 11:54 發表


Let X be the quantity of $50cents coins, and Y be the quanity of $2 coins

X + Y = 30

0.5X + 2Y = 42

you need to try to solve the equation by yourself, otherwise you cannot improve your mathematic ...

Rank: 6Rank: 6


5339
6#
發表於 08-3-18 17:10 |只看該作者
長老真係精靈
凡事都有定期 、 天下萬務都有定時 . 生有時 、 死有時 .

Rank: 6Rank: 6


9583
7#
發表於 08-3-18 21:29 |只看該作者
46,

長老的老不可與你的"老"同日而語喎:;pppp: :;pppp:

原文章由 正46 於 08-3-18 14:24 發表
長老真係寶刀未老!



241
8#
發表於 08-3-18 22:49 |只看該作者

回覆 #7 crystalwesley 的文章

提示: 作者被禁止或刪除 內容自動屏蔽

Rank: 4


731
9#
發表於 08-3-18 23:29 |只看該作者
Let X be the quantity of $50cents coins,
then the quanity of $2 coins will be 30-X.


0.5X + 2(30-X) = 42
0.5X + 60 - 2X = 42
   60 - 1.5X        = 42
   60 - 42           = 1.5X

then  X = 12  (the quantity of $50cents coins)

the quanity of $2 coins will be 30-X = 30 - 12 = 18...


This maybe F.1 or F.2 question

can use either 1 or 2 unknown equation

Rank: 4


761
10#
發表於 08-3-19 21:49 |只看該作者
多謝你們的回應呀!  這是中一的數呀! thanks a lot!!!!

Rank: 3Rank: 3


127
11#
發表於 08-3-30 23:46 |只看該作者
goodgood ar~
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