Jean had 240 stickers. ²₅ were yellow and the rest were green and purple. The ratio of the number of green stickers to the number of purple stickers was 1 : 3. Jean decided to buy some more yellow stickers to increase the number of yellow stickers to half of the total number of stickers.

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

Yellow stickers	Green stickers	Purple stickers	Total
2x4	3x4
	1x3	3x3
8 u	3 u	9 u	240

	Yellow stickers	Green stickers	Purple stickers
Before	8 u	3 u	9 u
Change	+ ?
After	12 u	12 u
Comparing yellow, green and purple stickers in the end	1	1

(a)
The total number of green stickers and purple stickers is repeated. Make the total number of green stickers and purple stickers the same.  LCM of 3 and 4 is 12.

Total number of stickers at first
= 8 u + 3 u + 9 u
= 20 u

20 u = 240

1 u = 240 ÷ 20 = 12

Number of less green stickers than yellow stickers at first
= 8 u - 3 u
= 5 u
= 5 x 12
= 60

(b)
Number of more yellow stickers that Jean had to buy
= 12 u - 8 u
= 4 u
= 4 x 12
= 48

Answer(s): (a) 60; (b) 48