PSLE
Julie baked some shortbreads. She gave ¹₈ of the shortbreads to her relatives and 66 to her friends. She was left with ¹₂ of the shortbreads. She packed these into 10 boxes. Some boxes contained 7 shortbreads while the rest contained 10 shortbreads.

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

(a)
Fraction of the shortbreads given to her friends
= 1 - ¹₈ - ¹₂

= 1 - ¹₈ - ⁴₈
= ³₈

Number of shortbreads that Julie gave to her friends = 3 u

3 u = 66

1 u = 66 ÷ 3 = 22

Number of shortbreads that were packed in 10 boxes
= 4 u
= 4 x 22
= 88

Number of shortbreads that were packed in 10 boxes = 88

Boxes of 10	Shortbreads	Boxes of 7	Shortbreads	Total shortbreads
10	100	0	0	100
9	90	1	7	97

If all the shortbreads are packed in boxes of 10, the number of shortbreads needed
= 10 x 10
= 100

Small difference
= 100 - 97
= 3

Big difference
= 100 - 88
= 12

Number of boxes of 7 shortbreads 
= 12 ÷ 3
= 4

Number of boxes of 10 shortbreads
= 10 - 4
= 6

Answer(s): (a) 88; (b) 6