At first, Ben, Xylia and Carl had some chocolate bars in the ratio 5 : 3 : 4 respectively. Ben had 320 chocolate bars. Then he gave all his chocolate bars to Xylia and Carl. After receiving the chocolate bars from Ben, Xylia and Carl had the same number of chocolate bars. How many chocolate bars did Xylia receive from Ben?

	Ben	Xylia	Carl	Total
Before	5x1 = 5 u	3x1 = 3 u	4x1 = 4 u	12x1 = 12 u
Change	- 5 u	+ 5 u
After	0	1x6 = 6 u	1x6 = 6 u	2x6 = 12 u

The total number of chocolate bars remains unchanged. Make the total number of chocolate bars the same.  LCM of 2 and 12 is 12.

Total number of chocolate bars = 12 u

Number of chocolate bars that Xylia had in the end 
= 12 u ÷ 2
= 6 u

Number of chocolate bars that Ben had at first = 5 u 

5 u = 320

1 u = 320 ÷ 5 = 64

Number of chocolate bars that Xylia received from Ben
= 6 u - 3 u
= 3 u
= 3 x 64
= 192

Answer(s): 192