Class U, V and W were given some chocolate bars to sell for their charity drive. The average number of chocolate bars the 3 classes had at first was 213. After Class V sold twice as many chocolate bars as Class U and Class W sold ⁵₆ as many chocolate bars as Class V, the average number of chocolate bars the 3 classes had left was 45. How many chocolate bars did Class U and Class W sell altogether?

Class U	Class V	Class W
1x3	2x3
	6x1	5x1
3 u	6 u	5 u

Class U : Class V : Class W
3 : 6 : 5

Total number of chocolate bars that the 3 classes had at first
= 3 x 213
= 639

Number of chocolate bars that the 3 classes left
= 3 x 45 
= 135

Number of chocolate bars that were sold by 3 classes
= 639 - 135
= 504

3 u + 6 u + 5 u = 504
14 u = 504

1 u = 504 ÷ 14 = 36

Total number of chocolate bars sold by Class U and Class W
= 3 u + 5 u
= 8 u
= 8 x 36
= 288

Answer(s): 288