Fabian and Billy had 24 wafers altogether. After Fabian ate ¹₃ of his wafers and Billy ate 10 wafers, the number of wafers Billy had left was twice the number of wafers Fabian had left. How many more wafers did Billy have than Fabian at first?

	Fabian	Billy	Total
Before	3 u	4 u + 10	24
Change	- 1 u	- 10
After	2 u
Comparing Fabian and Billy in the end	1x2 = 2 u	2x2 = 4 u

The number of wafers that Fabian had in the end is the same. Make the number of wafers that Fabian had in the end the same.  LCM of 2 and 1 is 2.

Total number of wafers at first
= 3 u + 4 u + 10
= 7 u + 10

7 u + 10 = 24
7 u = 24 - 10
7 u = 14 

1 u = 14 ÷ 7 = 2

Number of wafers that Fabian had at first
= 3 u
= 3 x 2
= 6

Number of wafers that Billy had at first
= 24 - 6
= 18

Number of wafers that Billy had more than Fabian at first
= 18 - 6
= 12

Answer(s): 12