Lynn and Sarah had a total of 72 stickers. Sarah gave ¹₃ of her stickers to Lynn. In return, Lynn gave ¹₇ of the total number of stickers that she had to Sarah. In the end, each girl had the same number of stickers. How many stickers did Lynn have at first?

	Lynn	Sarah	Total
Before 1	?	3 u	72
Change 1	+ 1 u	- 1 u
After 1	42	2 u	72
Before 2	7 p	2 u	72
Change 2	- 1 p	+ 1 p
After 2	6 p (36)	36	72

Since Sarah gave some stickers to Lynn and Lynn then gave some stickers to Sarah, it is an internal transfer of stickers between the two girls. So, the total number of stickers remains unchanged.

Number of stickers that Sarah and Lynn each had in the end is the same.

Number of stickers that Lynn had in the end
= 72 ÷ 2
= 36

Number of stickers that Lynn had in the end = 6 p

6 p = 36

1 p = 36 ÷ 6 = 6

Number of stickers that Lynn had after receiving some stickers from Sarah
= 7 p
= 7 x 6
= 42

Number of stickers that Sarah had after giving to Lynn
= 72 - 42
= 30

2 u = 30

1 u = 30 ÷ 2 = 15

Number of stickers that Sarah had at first
= 3 u
= 3 x 15
= 45

Number of stickers that Lynn had at first
= 72 - 45
= 27

Answer(s): 27