Class W, X and Y were given some chocolate bars to sell for their donation drive. The average number of chocolate bars the 3 classes had at first was 240. After Class X sold thrice as many chocolate bars as Class W and Class Y sold ⁵₆ as many chocolate bars as Class X, the average number of chocolate bars the 3 classes had left was 58. How many chocolate bars did Class W and Class Y sell altogether?

Class W	Class X	Class Y
1x2	3x2
	6x1	5x1
2 u	6 u	5 u

Class W : Class X : Class Y
2 : 6 : 5

Total number of chocolate bars that the 3 classes had at first
= 3 x 240
= 720

Number of chocolate bars that the 3 classes left
= 3 x 58 
= 174

Number of chocolate bars that were sold by 3 classes
= 720 - 174
= 546

2 u + 6 u + 5 u = 546
13 u = 546

1 u = 546 ÷ 13 = 42

Total number of chocolate bars sold by Class W and Class Y
= 2 u + 5 u
= 7 u
= 7 x 42
= 294

Answer(s): 294