Class U, V and W were given some mochi balls to sell for their fund-raising project. The average number of mochi balls the 3 classes had at first was 228. After Class V sold thrice as many mochi balls as Class U and Class W sold ⁵₆ as many mochi balls as Class V, the average number of mochi balls the 3 classes had left was 59. How many mochi balls did Class U and Class W sell altogether?

Class U	Class V	Class W
1x2	3x2
	6x1	5x1
2 u	6 u	5 u

Class U : Class V : Class W
2 : 6 : 5

Total number of mochi balls that the 3 classes had at first
= 3 x 228
= 684

Number of mochi balls that the 3 classes left
= 3 x 59 
= 177

Number of mochi balls that were sold by 3 classes
= 684 - 177
= 507

2 u + 6 u + 5 u = 507
13 u = 507

1 u = 507 ÷ 13 = 39

Total number of mochi balls sold by Class U and Class W
= 2 u + 5 u
= 7 u
= 7 x 39
= 273

Answer(s): 273