There were white, gold and green marbles in a container. Sean put another 10 white marbles and 2 green marbles in the container, then the ratio of the number of gold marbles to the number of green marbles became 5 : 3. Then, he doubled the number of white marbles and removed 30 green marbles. The ratio of the number of white marbles to gold marbles became 2 : 1. He counted and found that there were a total of 132 marbles left in the container. Find the number of white marbles that he had in the end.

	White marbles	Gold marbles	Green marbles	Total
Before	5 u - 10	5 u	3 u - 2
Change 1	+ 10		+ 2
After 1	1x5 = 5 u	5 u	3 u
Change 2	+ 1x5 = 5 u		- 30
After 2	2x5 = 10 u	1x5 = 5 u	3 u - 30	132

The number of gold marbles remains unchanged. Make the number of gold marbles the same. LCM of 1 and 5 is 5.

Total number of marbles in the end
= 10 u + 5 u + 3 u - 30
= 18 u - 30

18 u - 30 = 132
18 u = 132 + 30
18 u = 162

1 u = 162 ÷ 18 = 9

Number of white marbles in the end
= 10 u 
= 10 x 9
= 90

Answer(s): 90