PSLE
Nora bought some chocolate bars and gave half of it to Owen. Owen bought some lollipops and gave half of it to Nora. Nora ate 3 lollipops and Owen ate 14 chocolate bars. The ratio of Nora's lollipops to chocolate bars became 1 : 4 and the ratio of Owen's lollipops to chocolate bars became 1 : 2. How many chocolate bars did Nora buy?

	Nora		Owen
	Lollipops	Chocolate bars	Lollipops	Chocolate bars
Before	1 u + 3	4 u	1 p	2 p + 14
Change	- 3			- 14
After	1 u	4 u	1 p	2 p

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

4 u = 2 p + 14 
4 u - 14 = 2 p --- (1)

1 u + 3 = 1 p --- (2)

Make p the same.

(2)_x2
2 u + 6 = 2 p --- (3)

(1) = (3)
4 u - 14 = 2 u + 6 
4 u - 2 u = 6 + 14
2 u = 20

1 u = 20 ÷ 2 = 10

Number of chocolate bars that Nora bought
= 2 x 4 u
= 8 u
= 8 x 10
= 80

Answer(s): 80