Albert and Billy had 92 marbles in total. Albert had 24 marbles less than Billy at first. After Albert and Billy played a game with Anna, Albert had ¹₅ as many marbles as Billy. If Albert lost as many marbles as Billy to Anna, find the number of marbles that Billy lost to Anna.

	Albert	Billy	Difference
Before	1 u	1 u + 24	24
Change	- ?	- ?
After	1 p	5 p	4 p

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

2 u + 24 = 92
2 u = 92 - 24
2 u = 68

1 u = 68 ÷ 2 = 34

Since Albert lost the same number of marbles as Billy, the difference in the number of marbles between Albert and Billy at first and in the end remains the same.

Difference in the number of marbles in the end
= 5 p - 1 p
= 4 p

4 p = 24

1 p = 24 ÷ 4 = 6

Number of marbles that Albert lost to Anna
= 1 u - 1 p
= 34 - 1 x 6
= 34 - 6
= 28

Since Billy lost the same number of marbles as Albert, the number of marbles that each lost to Anna is the same.

Number of marbles that Billy lost = 28

Answer(s): 28