PSLE
Victoria baked some shortbreads. She gave ¹₁₀ of the shortbreads to her friends and 64 to her relatives. She was left with ¹₂ of the shortbreads. She packed these into 10 boxes. Some boxes contained 5 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 relatives
= 1 - ¹₁₀ - ¹₂

= 1 - ¹₁₀ - ⁵₁₀
= ⁴₁₀

Number of shortbreads that Victoria gave to her relatives = 4 u

4 u = 64

1 u = 64 ÷ 4 = 16

Number of shortbreads that were packed in 10 boxes
= 5 u
= 5 x 16
= 80

Number of shortbreads that were packed in 10 boxes = 80

Boxes of 10	Shortbreads	Boxes of 5	Shortbreads	Total shortbreads
10	100	0	0	100
9	90	1	5	95

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

Small difference
= 100 - 95
= 5

Big difference
= 100 - 80
= 20

Number of boxes of 5 shortbreads 
= 20 ÷ 5
= 4

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

Answer(s): (a) 80; (b) 6