PSLE
Emma baked some puffs. She gave ¹₆ of the puffs to her friends and 54 to her relatives. She was left with ¹₂ of the puffs. She packed these into 13 boxes. Some boxes contained 5 puffs while the rest contained 7 puffs.

1. How many puffs were packed into the 13 boxes?
2. How many boxes contained 7 puffs?

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

= 1 - ¹₆ - ³₆
= ²₆

Number of puffs that Emma gave to her relatives = 2 u

2 u = 54

1 u = 54 ÷ 2 = 27

Number of puffs that were packed in 13 boxes
= 3 u
= 3 x 27
= 81

Number of puffs that were packed in 13 boxes = 81

Boxes of 7	Puffs	Boxes of 5	Puffs	Total puffs
13	91	0	0	91
12	84	1	5	89

If all the puffs are packed in boxes of 7, the number of puffs needed
= 13 x 7
= 91

Small difference
= 91 - 89
= 2

Big difference
= 91 - 81
= 10

Number of boxes of 5 puffs 
= 10 ÷ 2
= 5

Number of boxes of 7 puffs
= 13 - 5
= 8

Answer(s): (a) 81; (b) 8