有兩條英文數學題唔識，係方程式 (要有步驟) !Help!急需!10點 THX

1) Let the ten digit of the number be x, the unit digit be y.
(10x + y) / 2 = 6x - 4
10x + y = 12x - 8
therefore y = 2x - 8
The posisible answers of (x, y) are (4, 0), (5, 2), (6, 4), (7, 6) and (8, 8)
As the number is divisible by both 2 and 5, so the possible answer is only 40.

2) Let the number of chickens be x, so
2x + 3(35 - x)(1/3) + 4(35 - x)(2/3) = 90
6x + 105 - 3x + 280 - 8x = 270
5x = 115
therefore x = 23
(35 - x)(1/3) = 4
(35 - x)(2/3) = 8
So, there are 23 chickens, 8 rabbits with 4 legs.

(1). Let the tens digit be a, units digit be b
(10a + b) / 2 = 6a - 4
10a + b = 12a - 8
b = 2a - 8
Possible numbers: 80 & 91
Only 80 can be divisible by 2 & 5
Therefore, the number is 80

(2). (a). Let the number of chicken be a, number of rabbit be (35 - a)
2a + 1/3 (35 - a) (3) + 2/3 (35 - a) (4) = 90
6a + 105 - 3a +280 - 8a = 270
5a = 160
a = 32
There are 32 chickens.

(b). There are 35 - 32 = 3 rabbits
There are 3 (2/3) = 2 rabbits with 4 legs

2006-10-22 21:36:11 補充：
Sorry 我計錯左^_^"應該係 40, 52, 64, 76, 88...the number should be 40...

2006-10-22 21:41:03 補充：
Sorry 我又計錯…=_="5a = 115a = 23There are 23 chickens.There are 35 - 23 = 12 rabbitsThere are 12 (2/3) = 8 rabbits with 4 legs 由於我成日計錯，所以你俾「最佳回答」下面既回答者，我覺得更適合你俾我既話，我仲會覺得唔好意思…^_^"