Class X, Y and Z were given some mini cupcakes to sell for their charity drive. The average number of mini cupcakes the 3 classes had at first was 206. After Class Y sold four times as many mini cupcakes as Class X and Class Z sold ²₃ as many mini cupcakes as Class Y, the average number of mini cupcakes the 3 classes had left was 45. How many mini cupcakes did Class X and Class Z sell altogether?

Class X	Class Y	Class Z
1x3	4x3
	3x4	2x4
3 u	12 u	8 u

Class X : Class Y : Class Z
3 : 12 : 8

Total number of mini cupcakes that the 3 classes had at first
= 3 x 206
= 618

Number of mini cupcakes that the 3 classes left
= 3 x 45 
= 135

Number of mini cupcakes that were sold by 3 classes
= 618 - 135
= 483

3 u + 12 u + 8 u = 483
23 u = 483

1 u = 483 ÷ 23 = 21

Total number of mini cupcakes sold by Class X and Class Z
= 3 u + 8 u
= 11 u
= 11 x 21
= 231

Answer(s): 231