Pierre and Jeremy had 87 beads in total. Jeremy had 21 beads more than Pierre at first. After Pierre and Jeremy played a game with Sarah, Pierre had ¹₈ as many beads as Jeremy. If Pierre lost as many beads as Jeremy to Sarah, find the number of beads that Pierre lost to Sarah.

	Pierre	Jeremy	Difference
Before	1 u	1 u + 21	21
Change	- ?	- ?
After	1 p	8 p	7 p

Total number of beads at first
= 1 u + 1 u + 21 
= 2 u + 21

2 u + 21 = 87
2 u = 87 - 21
2 u = 66

1 u = 66 ÷ 2 = 33

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

Difference in the number of beads in the end
= 8 p - 1 p
= 7 p

7 p = 21

1 p = 21 ÷ 7 = 3

Number of beads that Pierre lost to Sarah
= 1 u - 1 p
= 33 - 1 x 3
= 33 - 3
= 30

Answer(s): 30