趣味數學(10分)

Let 餅:c , 香腸:s , 香蕉:b
2c+1s=2s+2b --> 2c=s+2b .....(1)
1c+2s=3b .....(2)
from (1)&(2) s+2b=6b-4s --> 5s=4b

5c+2s
=15b-10s+2s (from (2))
=15b-8s
=15b-6.4b
=8.6b

5餅+2香腸 = 8.6個香蕉

2006-11-24 14:53:19 補充：
如果答案只有: a3 b4 c7 d11 我會刪哂D答案寫番自己果個, 如果答案要係整數, 明顯問題出錯左.

2006-11-24 14:56:17 補充：
應該呢度較大可能出錯:2餅+1香腸=2香腸+2香蕉等式左右都有香腸... 點解唔直接寫 "2餅=1香腸+2香蕉" 呢?

設
餅=A
香腸=B
香蕉=C
2A+1B=2B+2C 1A+2B=3C
2A=B+2C 3C=1A+2B
2A-B=2C
(2A-B)x1.5=1A+2B
3A-1.5B=1A+2B
2A=3.5B
A=1.75B
設A為70,所以B為40.
140+40=80+2C
180=80+2C
100=2C
C=50

A=70
B=40
C=50

5x70+2x40=?x50
350+80=?x50
430=?x50
?=430/50
?=8.6

8.6隻香蕉.

餅=x
香腸=y
香蕉=z

2餅+1香腸=2香腸+2香蕉
2x+y=2y+2z
2x-2z=y --------------------(1)

1餅+2香腸=3香蕉
x+2y=3z
x=3z-2y -------------------(2)

put 2 into 1
2(3z-2y)-2z=y

6z-4y-2z=y
4z=5y --------------------(3)

put 3 into 2
x=3z-2(4/5z)

5餅+2香腸=?香蕉
5x+2y
=5[3z-2(4/5z)] +2(4/5z)
=15z-8z+8/5z

2餅+1香腸=2香腸+2香蕉
=>2餅=1香腸+2香蕉
=>1香腸 = 2餅 - 2香蕉 -----------(1)

1餅+2香腸=3香蕉 -----------------(2)
代(1)進(2)
1餅+2(2餅 - 2香蕉)=3香蕉
=>1餅 + 4餅 - 4香蕉=3香蕉
=>5餅 =7香蕉
=>1餅 =7/5香蕉---------------------(3)

代(3)進(1)
1香腸 = 2(7/5香蕉) - 2香蕉
=>1香腸 = 14/5香蕉 - 2香蕉
=>1香腸 = 4/5香蕉-----------------(4)

5餅+2香腸----------------------------(5)
代(3)和(4)進(5)
5(7/5香蕉)+2(4/5香蕉)
=>7香蕉+8/5香蕉
=>8 (3/5)香蕉

5隻香蕉
因為餅其實係香蕉
香腸都係香腸, 只不過係混淆左