PSLE
Yen baked some cupcakes. She gave ²₅ of the cupcakes to her students and 126 to her friends. She was left with ¹₄ of the cupcakes. She packed these into 10 boxes. Some boxes contained 6 cupcakes while the rest contained 11 cupcakes.

1. How many cupcakes were packed into the 10 boxes?
2. How many boxes contained 11 cupcakes?

(a)
Fraction of the cupcakes given to her friends
= 1 - ²₅ - ¹₄

= 1 - ⁸₂₀ - ⁵₂₀
= ⁷₂₀

Number of cupcakes that Yen gave to her friends = 7 u

7 u = 126

1 u = 126 ÷ 7 = 18

Number of cupcakes that were packed in 10 boxes
= 5 u
= 5 x 18
= 90

Number of cupcakes that were packed in 10 boxes = 90

Boxes of 11	Cupcakes	Boxes of 6	Cupcakes	Total cupcakes
10	110	0	0	110
9	99	1	6	105

If all the cupcakes are packed in boxes of 11, the number of cupcakes needed
= 10 x 11
= 110

Small difference
= 110 - 105
= 5

Big difference
= 110 - 90
= 20

Number of boxes of 6 cupcakes 
= 20 ÷ 5
= 4

Number of boxes of 11 cupcakes
= 10 - 4
= 6

Answer(s): (a) 90; (b) 6