PSLE
Winnie bought some lollipops and gave half of it to Japheth. Japheth bought some chocolate bars and gave half of it to Winnie. Winnie ate 7 chocolate bars and Japheth ate 5 lollipops. The ratio of Winnie's chocolate bars to lollipops became 1 : 5 and the ratio of Japheth's chocolate bars to lollipops became 1 : 3. How many lollipops did Winnie buy?

	Winnie		Japheth
	Chocolate bars	Lollipops	Chocolate bars	Lollipops
Before	1 u + 7	5 u	1 p	3 p + 5
Change	- 7			- 5
After	1 u	5 u	1 p	3 p

After Winnie gave half of the lollipops to Japheth and Japheth gave half of his chocolate bars to Winnie, Japheth and Winnie had same number of chocolate bars and lollipops before each ate some.

5 u = 3 p + 5 
5 u - 5 = 3 p --- (1)

1 u + 7 = 1 p --- (2)

Make p the same.

(2)_x3
3 u + 21 = 3 p --- (3)

(1) = (3)
5 u - 5 = 3 u + 21 
5 u - 3 u = 21 + 5
2 u = 26

1 u = 26 ÷ 2 = 13

Number of lollipops that Winnie bought
= 2 x 5 u
= 10 u
= 10 x 13
= 130

Answer(s): 130