Class M, N and P were given some mochi balls to sell for their charity drive. The average number of mochi balls the 3 classes had at first was 233. After Class N sold twice as many mochi balls as Class M and Class P sold ⁴₅ as many mochi balls as Class N, the average number of mochi balls the 3 classes had left was 49. How many mochi balls did Class M and Class P sell altogether?

Class M	Class N	Class P
1x5	2x5
	5x2	4x2
5 u	10 u	8 u

Class M : Class N : Class P
5 : 10 : 8

Total number of mochi balls that the 3 classes had at first
= 3 x 233
= 699

Number of mochi balls that the 3 classes left
= 3 x 49 
= 147

Number of mochi balls that were sold by 3 classes
= 699 - 147
= 552

5 u + 10 u + 8 u = 552
23 u = 552

1 u = 552 ÷ 23 = 24

Total number of mochi balls sold by Class M and Class P
= 5 u + 8 u
= 13 u
= 13 x 24
= 312

Answer(s): 312