一些F.1英文ge maths問題..@@20分@@

[1]

Let n be the no. of 0.5-kg packs of sugar.

Then, no. of 2-kg packs of sugar = 130 - n

Total weights of all the 130 packs of sugar.

0.5n + 2(130 - n) = 134

0.5 n + 260 - 2n = 134

-1.5 n = -126

n = 84

Ans: 84 packs of sugar weigh 0.5 kg each.

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[2]

Let $A be the price of model house A.

Then, price of model house B = $(A + 6)

The total price of 5 model houses A and 3 model houses B:

5A + 3(A + 6) = 210

5A + 3A + 18 = 210

8A + 18 = 210

8A = 192

A = 24

Ans: The price of a model house A is $24.
=

因為我已經離學左學校好耐，所以唔知依d係咪你學梗既野:

1) Let x be the packs of sugar weigh 0.5kg and y be the packs of sugar weigh 2kg.

x+y=130
0.5x + 2y = 134

x+y=130
y=130-x

0.5x+2y=134
0.5x+2(130-x)=134
0.5x+260-2x=134
1.5x=126
x=84

x+y=130
84+y=130
y=46

2) Let x be the price of model house A and y be the price of model house B.
x=y-6
5x+3y=210

5(y-6)+3y=210
5y-30+3y=210
8y=240
y=30
x=y-6
x=30-6
x=24

(1)
let x be the number of 0.5kg sugar
let y be the number of 2kg sugar

x+y=130←(1)
0.5x+2y=134←(2)
(1)*2,
2x+2y=260←(3)
(3)-(2),
1.5x=126
x=84
sub x=84 into (1)
84+y=130
y=46
∴the number of 0.5kg sugar is 84,
the number of 2kg sugar is 46
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(2)
let the value of the model house A be x
let the value of the model house B be y

x+6=y←(1)
5x+3y=210←(2)
(1)*3,
3x+18=3y
3y-3x=18←(3)
(2)-(3),
2x=192
x=96
sub x=96 to (1),
96+6=y
y=102
∴ the value of the model house A is 96
the value of the model house B is 102
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Hope all these can help you...^^