There are 70 stickers in Container Q and 50 stickers in Container R.
Some stickers are transferred from Container Q to Container R.
Container R has 30 more stickers than Container Q.
How many stickers are transferred from Container Q to Container R?

	Container Q	Container R
Before	70	50
Change	- ?	+ ?
After	1 u	1 u + 30

Total number of stickers
= 70 + 50
= 120

In the end
Total number of stickers = 1 u + 1 u + 30 = 2 u + 30

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

2 u + 30 = 120
2 u = 120 - 30 = 90

1 u = 90 ÷ 2 = 45

Number of stickers that are transferred from Container Q to Container R
= Number of stickers in Container Q at first - Number of stickers in Container Q in the end
= 70 - 45
= 25

Answer(s): 25