Class D, E and F were given some mini cupcakes to sell for their fund-raising project. The average number of mini cupcakes the 3 classes had at first was 226. After Class E sold thrice as many mini cupcakes as Class D and Class F sold ³₄ as many mini cupcakes as Class E, the average number of mini cupcakes the 3 classes had left was 51. How many mini cupcakes did Class D and Class F sell altogether?

Class D	Class E	Class F
1x4	3x4
	4x3	3x3
4 u	12 u	9 u

Class D : Class E : Class F
4 : 12 : 9

Total number of mini cupcakes that the 3 classes had at first
= 3 x 226
= 678

Number of mini cupcakes that the 3 classes left
= 3 x 51 
= 153

Number of mini cupcakes that were sold by 3 classes
= 678 - 153
= 525

4 u + 12 u + 9 u = 525
25 u = 525

1 u = 525 ÷ 25 = 21

Total number of mini cupcakes sold by Class D and Class F
= 4 u + 9 u
= 13 u
= 13 x 21
= 273

Answer(s): 273