PSLE
Gwen baked some puffs. She gave ¹₆ of the puffs to her students and 90 to her colleagues. She was left with ¹₂ of the puffs. She packed these into 17 boxes. Some boxes contained 6 puffs while the rest contained 9 puffs.

1. How many puffs were packed into the 17 boxes?
2. How many boxes contained 9 puffs?

(a)
Fraction of the puffs given to her colleagues
= 1 - ¹₆ - ¹₂

= 1 - ¹₆ - ³₆
= ²₆

Number of puffs that Gwen gave to her colleagues = 2 u

2 u = 90

1 u = 90 ÷ 2 = 45

Number of puffs that were packed in 17 boxes
= 3 u
= 3 x 45
= 135

Number of puffs that were packed in 17 boxes = 135

Boxes of 9	Puffs	Boxes of 6	Puffs	Total puffs
17	153	0	0	153
16	144	1	6	150

If all the puffs are packed in boxes of 9, the number of puffs needed
= 17 x 9
= 153

Small difference
= 153 - 150
= 3

Big difference
= 153 - 135
= 18

Number of boxes of 6 puffs 
= 18 ÷ 3
= 6

Number of boxes of 9 puffs
= 17 - 6
= 11

Answer(s): (a) 135; (b) 11