F.2 Simultaneous Linear Equations in Two Unknowns(1)

2. let x,y be the weight of letter and parcel:
x+y = 238 -----1
3x = 16y -----2
From2 x = 16y/3 -----3
Put 3 into 1
16y/3 + y = 238
19y = 714
y = 37.8g(3s.f.)
Put y = 37.8 into 1
x = 200g(3s.f.)
3. Letx,y be the $5 coins and $0.5 coins:
x+y = 20 -----1
5x+0.5y = 64 -----2
From1 y = 20 - x -----3
Put 3 into 2
5x + (10 - 0.5x) = 64
4.5x = 54
x = 12
So there are 12 $5 coins

2007-02-21 15:56:21 補充：
比10分我啦!!我係第一個比answer你既人呀!!Please...

2007-02-21 15:57:24 補充：
but 第一題我睇唔明(If 有中文,比我睇)

2007-02-21 15:57:25 補充：
but 第一題我睇唔明(If 有中文,比我睇)

2007-02-22 10:59:14 補充：
2.so weight of letter is 200g , weight of parcel is 38g

2007-02-22 12:52:21 補充：
2. let x,y be the weight of letter and parcel:x y = 238 -----13x = 1/16y -----2From2 x = y/48 -----3Put 3 into 1y/48 y = 23849y = 11424y = 233g(3s.f.)Put y = 233 into 1x = 4.86g(3s.f.)so weight of letter is 5g , weight of parcel is 233g

1. 計唔到整數, 唔知有無錯

Let x be the number of group photos
Let y be the number of individual photos

x+y = 44 --- (1)
2y = x ---- (2)

代 (2) 入 (1)
所以 x = 29 , y = 15 (4捨5入)

2.
Let x be the weight of letter
Let y be the weight of the parcel

x + y = 238 --- (1)
3x = 1/6 y --- (2)

代 (1) 入 (2), x= 12.53 , y = 225.47

therefore parcel weighs 225.47g.

3.
Let x be the number of $5 coins
Let y be the number of $0.5 coins

5x + 0.5 y = 64 --- (1)
x +y = 20 ---- (2)

代 (2 入 (1), x= 12 , y = 8

therefore, there are 12 $5 coins