There are 85 stickers in Container Q and 40 stickers in Container R.
Some stickers are transferred from Container Q to Container R.
Container Q has 15 more stickers than Container R.
How many stickers are transferred from Container Q to Container R?

	Container Q	Container R
Before	85	40
Change	- ?	+ ?
After	1 u + 15	1 u

Total number of stickers
= 85 + 40
= 125

Total number of stickers in the end = 1 u + 15 + 1 u = 2 u + 15

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

2 u + 15 = 125
2 u = 125 - 15 = 110

1 u = 110 ÷ 2 = 55

Number of stickers that are transferred from Container Q to Container R
= Number of stickers in Container R in the end - Number of stickers in Container R at first
= 55 - 40
= 15

Answer(s): 15