Class N, P and Q were given some chocolate bars to sell for their charity drive. The average number of chocolate bars the 3 classes had at first was 201. After Class P sold twice as many chocolate bars as Class N and Class Q sold ³₄ as many chocolate bars as Class P, the average number of chocolate bars the 3 classes had left was 51. How many chocolate bars did Class N and Class Q sell altogether?

Class N	Class P	Class Q
1x2	2x2
	4x1	3x1
2 u	4 u	3 u

Class N : Class P : Class Q
2 : 4 : 3

Total number of chocolate bars that the 3 classes had at first
= 3 x 201
= 603

Number of chocolate bars that the 3 classes left
= 3 x 51 
= 153

Number of chocolate bars that were sold by 3 classes
= 603 - 153
= 450

2 u + 4 u + 3 u = 450
9 u = 450

1 u = 450 ÷ 9 = 50

Total number of chocolate bars sold by Class N and Class Q
= 2 u + 3 u
= 5 u
= 5 x 50
= 250

Answer(s): 250