Form1 Math題

卍文哥卍

John's savings is $300 more than his sister's.After giving $450 of his savings to his sister,John's savings becomes 2/5 of his sisters.How much savings do they have altogether?

supernova

比我會咁計

J-S=300 ... (i)
J-450=(S+450)*2/5 ... (ii)

solve (i) & (ii),
J+S=1400

小鋒仔

我計到800喎 ... 同上面小丁一樣

點解答案會1400... 可唔可以解下?

J-S=300 ... (i)
J-450=S*2/5 ... (ii)

(300+S)-450=S*2/5
-150 = S(2/5-1)
S=250 ... (iii)

sub(iii)to(i)
J-250=300
J=550

TOTAL=J+S=250+550=800

[ 本帖最後由 小鋒仔 於 09-10-21 01:20 AM 編輯 ]

yoshua

原帖由 【小丁】 於 09-10-18 02:24 PM 發表

750-450之後都唔= 2/5 既450- -?定係我睇錯題目??

john有x元冇左450後剩下原本2/5嗎。咩唔係咩??
google都係咁translate

[ 本帖最後由 yoshua 於 09-10-18 05:41 PM 編輯 ]

卍文哥卍

答案已找出
係1400

【小丁】

原帖由 yoshua 於 09-10-18 02:19 PM 發表
設John有x元
    x-450=2x/5
5x-2250=2x
           x=750
john有750,sister有750-300=450
total750+450=1200

750-450之後都唔= 2/5 既450- -?定係我睇錯題目??

【小丁】

let john's sister save $x
that john save x+300
(x+300)-450=2/5x
3/5x=150
x=250
total =250+300+250 =800$

if correct good plx

yoshua

設John有x元
    x-450=2x/5
5x-2250=2x
           x=750
john有750,sister有750-300=450
total750+450=1200

卍文哥卍

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