Andy and Ken had 88 beads in total. Ken had 20 beads more than Andy at first. After Andy and Ken played a game with Gwen, Andy had ³₇ as many beads as Ken. If Andy lost as many beads as Ken to Gwen, find the number of beads that Andy lost to Gwen.

	Andy	Ken	Difference
Before	1 u	1 u + 20	20
Change	- ?	- ?
After	3 p	7 p	4 p

Total number of beads at first
= 1 u + 1 u + 20 
= 2 u + 20

2 u + 20 = 88
2 u = 88 - 20
2 u = 68

1 u = 68 ÷ 2 = 34

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

Difference in the number of beads in the end
= 7 p - 3 p
= 4 p

4 p = 20

1 p = 20 ÷ 4 = 5

Number of beads that Andy lost to Gwen
= 1 u - 3 p
= 34 - 3 x 5
= 34 - 15
= 19

Answer(s): 19