Three containers, C, A and B, contained 240 marbles. Tim added some marbles into Container C and the number of marbles in Container C tripled. He took out half of the number of marbles from Container A and removed 48 marbles from Container B. As a result, the ratio of the number of marbles in Container C, Container A and Container B became 9 : 3 : 7. What was the ratio of the number of marbles in Container B to the total number of marbles in Container C and Container A at first? Give the answer in its lowest term.

	Container C	Container A	Container B	Total
Before	1x3 = 3 u	2x3 = 6 u	7 u + 48	240
Change	+ 2x3 = + 6 u	- 1x3 = - 3 u	- 48
After	3x3 = 9 u	1x3 = 3 u
Comparing the 3 containers	9 u	3 u	7 u

The number of marbles in Container C in the end is the same. Make the number of marbles in Container C in the end the same. LCM of 3 and 9 is 9.

The number of marbles in Container A in the end is the same. Make the number of marbles in Container A in the end the same. LCM of 1 and 3 is 3.

Total number of marbles at first
= 3 u + 6 u + 7 u + 48
= 16 u + 48

16 u + 48 = 240
16 u = 240 - 48
16 u = 192

1 u = 192 ÷ 16 = 12

Number of marbles in Container B at first
= 7 u + 48
= 7 x 12 + 48
= 84 + 48
= 132

Number of marbles in Container C and Container A at first
= 240 - 132
= 108

Container B : Container C and Container A
132 : 108 _(÷12)
11 : 9

Answer(s): 11 : 9