Luke and Vaidev had 78 stickers in total. Luke had 18 stickers less than Vaidev at first. After Luke and Vaidev played a game with Barbara, Luke had ²₁₁ as many stickers as Vaidev. If Luke lost as many stickers as Vaidev to Barbara, find the number of stickers that Vaidev lost to Barbara.

	Luke	Vaidev	Difference
Before	1 u	1 u + 18	18
Change	- ?	- ?
After	2 p	11 p	9 p

Total number of stickers at first
= 1 u + 1 u + 18 
= 2 u + 18

2 u + 18 = 78
2 u = 78 - 18
2 u = 60

1 u = 60 ÷ 2 = 30

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

Difference in the number of stickers in the end
= 11 p - 2 p
= 9 p

9 p = 18

1 p = 18 ÷ 9 = 2

Number of stickers that Luke lost to Barbara
= 1 u - 2 p
= 30 - 2 x 2
= 30 - 4
= 26

Since Vaidev lost the same number of stickers as Luke, the number of stickers that each lost to Barbara is the same.

Number of stickers that Vaidev lost = 26

Answer(s): 26