There were pink, blue and white beads in a box. Sean put another 4 pink beads and 9 white beads in the box, then the ratio of the number of blue beads to the number of white beads became 5 : 2. Then, he doubled the number of pink beads and removed 15 white beads. The ratio of the number of pink beads to blue beads became 2 : 1. He counted and found that there were a total of 70 beads left in the box. Find the number of pink beads that he had in the end.

	Pink beads	Blue beads	White beads	Total
Before	5 u - 4	5 u	2 u - 9
Change 1	+ 4		+ 9
After 1	1x5 = 5 u	5 u	2 u
Change 2	+ 1x5 = 5 u		- 15
After 2	2x5 = 10 u	1x5 = 5 u	2 u - 15	70

The number of blue beads remains unchanged. Make the number of blue beads the same. LCM of 1 and 5 is 5.

Total number of beads in the end
= 10 u + 5 u + 2 u - 15
= 17 u - 15

17 u - 15 = 70
17 u = 70 + 15
17 u = 85

1 u = 85 ÷ 17 = 5

Number of pink beads in the end
= 10 u 
= 10 x 5
= 50

Answer(s): 50