Pierre and Daniel had 60 stickers in total. Daniel had 24 stickers more than Pierre at first. After Pierre and Daniel played a game with Abi, Pierre had ¹₉ as many stickers as Daniel. If Pierre lost as many stickers as Daniel to Abi, find the number of stickers that Pierre lost to Abi.

	Pierre	Daniel	Difference
Before	1 u	1 u + 24	24
Change	- ?	- ?
After	1 p	9 p	8 p

Total number of stickers at first
= 1 u + 1 u + 24 
= 2 u + 24

2 u + 24 = 60
2 u = 60 - 24
2 u = 36

1 u = 36 ÷ 2 = 18

Since Pierre lost the same number of stickers as Daniel, the difference in the number of stickers between Pierre and Daniel at first and in the end remains the same.

Difference in the number of stickers in the end
= 9 p - 1 p
= 8 p

8 p = 24

1 p = 24 ÷ 8 = 3

Number of stickers that Pierre lost to Abi
= 1 u - 1 p
= 18 - 1 x 3
= 18 - 3
= 15

Answer(s): 15