PSLE
Vanessa bought some chocolate bars and gave half of it to Perry. Perry bought some jelly beans and gave half of it to Vanessa. Vanessa ate 2 jelly beans and Perry ate 18 chocolate bars. The ratio of Vanessa's jelly beans to chocolate bars became 1 : 6 and the ratio of Perry's jelly beans to chocolate bars became 1 : 3. How many chocolate bars did Vanessa buy?

	Vanessa		Perry
	Jelly beans	Chocolate bars	Jelly beans	Chocolate bars
Before	1 u + 2	6 u	1 p	3 p + 18
Change	- 2			- 18
After	1 u	6 u	1 p	3 p

After Vanessa gave half of the chocolate bars to Perry and Perry gave half of his jelly beans to Vanessa, Perry and Vanessa had same number of jelly beans and chocolate bars before each ate some.

6 u = 3 p + 18 
6 u - 18 = 3 p --- (1)

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

Make p the same.

(2)_x3
3 u + 6 = 3 p --- (3)

(1) = (3)
6 u - 18 = 3 u + 6 
6 u - 3 u = 6 + 18
3 u = 24

1 u = 24 ÷ 3 = 8

Number of chocolate bars that Vanessa bought
= 2 x 6 u
= 12 u
= 12 x 8
= 96

Answer(s): 96