Class Q, R and S were given some mini cupcakes to sell for their donation drive. The average number of mini cupcakes the 3 classes had at first was 217. After Class R sold twice as many mini cupcakes as Class Q and Class S sold ⁵₆ as many mini cupcakes as Class R, the average number of mini cupcakes the 3 classes had left was 49. How many mini cupcakes did Class Q and Class S sell altogether?

Class Q	Class R	Class S
1x3	2x3
	6x1	5x1
3 u	6 u	5 u

Class Q : Class R : Class S
3 : 6 : 5

Total number of mini cupcakes that the 3 classes had at first
= 3 x 217
= 651

Number of mini cupcakes that the 3 classes left
= 3 x 49 
= 147

Number of mini cupcakes that were sold by 3 classes
= 651 - 147
= 504

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

1 u = 504 ÷ 14 = 36

Total number of mini cupcakes sold by Class Q and Class S
= 3 u + 5 u
= 8 u
= 8 x 36
= 288

Answer(s): 288