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

	Cindy		Harry
	Sweets	Jelly beans	Sweets	Jelly beans
Before	1 u + 2	6 u	1 p	3 p + 18
Change	- 2			- 18
After	1 u	6 u	1 p	3 p

After Cindy gave half of the jelly beans to Harry and Harry gave half of his sweets to Cindy, Harry and Cindy had same number of sweets and jelly beans 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 jelly beans that Cindy bought
= 2 x 6 u
= 12 u
= 12 x 8
= 96

Answer(s): 96