英文數學中一題目

1.Let W denotes win, L denotes loss and T denotes tie.
As given,
W = L + 10 --- ( 1 )
L = T﹣2
T = L + 2 --- ( 2 )
Hence,
L + W + T = 24
L + L + 10 + L + 2 = 24
3L = 12
L = 4
Then T = 4+2 = 6 and W = 14
Hence no. of wins: 14, losses: 4, ties: 6

2.Let the cost of a keyboard be $x
8(x﹣20)+10 = 5x
8x﹣150 = 5x
3x = 150
x = 50
Hence,the cost of a keyboard is $50


2007-10-15 17:26:42 補充：
另一計法As follow：Let p be the cost of a keyboardand q be the cost of a mousep = q＋20　--- [1]5p = 8q＋10　--- [2]Sub [1] into [2]5(q＋20) = 8q＋105q＋100 = 8q＋103q = 90q = 30--- [3]Sub [3] into [1]p = 30 20 = 50So, the cost of a keyboard is $50.

2007-10-15 17:26:51 補充：
另一計法As follow：Let p be the cost of a keyboardand q be the cost of a mousep = q＋20　--- [1]5p = 8q＋10　--- [2]Sub [1] into [2]5(q＋20) = 8q＋105q＋100 = 8q＋103q = 90q = 30--- [3]Sub [3] into [1]p = 30 20 = 50So, the cost of a keyboard is $50.

2007-10-15 17:27:40 補充：
p = 30＋20 = 50

1) A hockey team played 24 games. The number of games that they won was 10 more than that they lost. The number of games that they lost was 2 less than that they tied. How many games did they win,lose and tie?(要列式+步驟)

有一組人玩咗24個遊戲,佢地贏左既遊戲比輸左多10個,同時,佢地輸既遊戲比打和少2個,咁佢地贏,輸,和既遊戲分別係幾多

let the games that they lose be n

(win)+(lost)+(tie)
(n+10)+n+(n+2) = 24

3n+12 = 24

3n = 12

n = 4

lose 4 games , win 14 games , tie 6 games

2) The cost of a keyboard is $20 more than that of a mouse. If Nelson buys 8 mouses, he has to pay $10 less than buying 5 keyboards. How much is a keyboard?

鍵盤既價錢比一個滑鼠貴$20,假如Nelson買左8隻滑鼠,佢要付出既錢係比買5個鍵盤少$10,咁1個鍵盤要幾錢?

let the price of a mouse be n

(8隻mouse+$10 = 5個keyboard)
8n+10 = (n+20)x5

8n+10 = 5n+100

3n = 90

n = 30

since the price of keyboard is $20 more than that if a mouse,keyboard's price is 30+20 = 50

2007-10-16 07:18:08 補充：
人地form 1 樓上你let 咁多未知數都幾勁喎