Shannon had 56 stickers. ²₇ were grey and the rest were pink and green. The ratio of the number of pink stickers to the number of green stickers was 1 : 3. Shannon decided to buy some more grey stickers to increase the number of grey stickers to half of the total number of stickers.

1. How many less pink stickers than grey stickers did he have at first?
2. How many more grey stickers did he have to buy?

Grey stickers	Pink stickers	Green stickers	Total
2x4	5x4
	1x5	3x5
8 u	5 u	15 u	56

	Grey stickers	Pink stickers	Green stickers
Before	8 u	5 u	15 u
Change	+ ?
After	20 u	20 u
Comparing grey, pink and green stickers in the end	1	1

(a)
The total number of pink stickers and green stickers is repeated. Make the total number of pink stickers and green stickers the same.  LCM of 5 and 4 is 20.

Total number of stickers at first
= 8 u + 5 u + 15 u
= 28 u

28 u = 56

1 u = 56 ÷ 28 = 2

Number of less pink stickers than grey stickers at first
= 8 u - 5 u
= 3 u
= 3 x 2
= 6

(b)
Number of more grey stickers that Shannon had to buy
= 20 u - 8 u
= 12 u
= 12 x 2
= 24

Answer(s): (a) 6; (b) 24