At first, Tommy, Kimberly and Riordan had some mochi balls in the ratio 8 : 6 : 7 respectively. Tommy had 288 mochi balls. Then he gave all his mochi balls to Kimberly and Riordan. After receiving the mochi balls from Tommy, Kimberly and Riordan had the same number of mochi balls. How many mochi balls did Kimberly receive from Tommy?

	Tommy	Kimberly	Riordan	Total
Before	8x2 = 16 u	6x2 = 12 u	7x2 = 14 u	21x2 = 42 u
Change	- 8 u	+ 8 u
After	0	1x21 = 21 u	1x21 = 21 u	2x21 = 42 u

The total number of mochi balls remains unchanged. Make the total number of mochi balls the same.  LCM of 2 and 21 is 42.

Total number of mochi balls = 42 u

Number of mochi balls that Kimberly had in the end 
= 42 u ÷ 2
= 21 u

Number of mochi balls that Tommy had at first = 8 u 

8 u = 288

1 u = 288 ÷ 8 = 36

Number of mochi balls that Kimberly received from Tommy
= 21 u - 12 u
= 9 u
= 9 x 36
= 324

Answer(s): 324