There are 90 stickers in Container X and 50 stickers in Container Y.
Some stickers are transferred from Container X to Container Y.
Container Y has 10 more stickers than Container X.
How many stickers are transferred from Container X to Container Y?

	Container X	Container Y
Before	90	50
Change	- ?	+ ?
After	1 u	1 u + 10

Total number of stickers
= 90 + 50
= 140

In the end
Total number of stickers = 1 u + 1 u + 10 = 2 u + 10

The total number of stickers at first and in the end remains unchanged.

2 u + 10 = 140
2 u = 140 - 10 = 130

1 u = 130 ÷ 2 = 65

Number of stickers that are transferred from Container X to Container Y
= Number of stickers in Container X at first - Number of stickers in Container X in the end
= 90 - 65
= 25

Answer(s): 25