There were pink, purple and blue balls in a container. Sean put another 2 pink balls and 3 blue balls in the container, then the ratio of the number of purple balls to the number of blue balls became 4 : 3. Then, he doubled the number of pink balls and removed 12 blue balls. The ratio of the number of pink balls to purple balls became 2 : 1. He counted and found that there were a total of 108 balls left in the container. Find the number of pink balls that he had in the end.

	Pink balls	Purple balls	Blue balls	Total
Before	4 u - 2	4 u	3 u - 3
Change 1	+ 2		+ 3
After 1	1x4 = 4 u	4 u	3 u
Change 2	+ 1x4 = 4 u		- 12
After 2	2x4 = 8 u	1x4 = 4 u	3 u - 12	108

The number of purple balls remains unchanged. Make the number of purple balls the same. LCM of 1 and 4 is 4.

Total number of balls in the end
= 8 u + 4 u + 3 u - 12
= 15 u - 12

15 u - 12 = 108
15 u = 108 + 12
15 u = 120

1 u = 120 ÷ 15 = 8

Number of pink balls in the end
= 8 u 
= 8 x 8
= 64

Answer(s): 64