Ratio Question,Please Help!!

2a = 3b
2a / b = 3
a/b = 3/2
a : b = 3 : 2 = 15 : 10
4b = 5c
4b / c = 5
b/c = 5/4
b : c = 5 : 4 = 10 : 8
a : b : c = 15 : 10 : 8


2007-04-03 18:07:15 補充：
下面果位朋友計錯數喇~

2007-04-03 18:10:12 補充：
如果唔信, 可以代入 a = 15, b = 10, c = 8 黎驗算一下~a = 15, 2a = 30b = 10, 3b = 30所以 2a = 3b, 符合第一個條件b = 10, 4b = 40c = 8, 5c = 40所以 4b = 5c, 符合第二個條件

2007-04-03 18:14:13 補充：
你可以代 a,b,c 的任何倍數入去即係, 15n, 10n, 8n ( n≠0, 而且 n 必須為同一數值 )無論 n 等於幾多, 都一定會符合上述兩個條件

2a=3b and 4b=5c
a:b = 3:2 and b:c = 5:4

-a : b___ = 3 : 2
___ b : c =___5 : 4
-------------------------------
-a : b : c = 15 : 10 : 8

_____-->有空格的

I think it is:
8:12:15

2a=3b
4b=5c
a | b | c
2 3
4 5
-----------
3 not =4
so
LCM
2X4 3X4
4X3 5X3
3X4=4X3
2X4:3X4:5X3
8:12:15

If 2a=3b then I can multiple both sides by 4
=> 4x2a=4x3b
=> 8a=12b


If 4b=5c then I can multiple both sides by 3
=> 3x4b=3x5c
=> 12b=15c

combine the above 2 statements I can get:
8a=12b & 12b=15c
=> 8a=12b=15c
=> ratio of a:b:c = 8:12:15