PSLE
Marion bought some jelly beans and gave half of it to Perry. Perry bought some lollipops and gave half of it to Marion. Marion ate 3 lollipops and Perry ate 36 jelly beans. The ratio of Marion's lollipops to jelly beans became 1 : 6 and the ratio of Perry's lollipops to jelly beans became 1 : 3. How many lollipops did Perry buy?

	Marion		Perry
	Lollipops	Jelly beans	Lollipops	Jelly beans
Before	1 u + 3	6 u	1 p	3 p + 36
Change	- 3			- 36
After	1 u	6 u	1 p	3 p

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

6 u = 3 p + 36 
6 u - 36 = 3 p --- (1)

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

Make p the same.

(2)_x3
3 u + 9 = 3 p --- (3)

(1) = (3)
6 u - 36 = 3 u + 9 
6 u - 3 u = 9 + 36
3 u = 45

1 u = 45 ÷ 3 = 15

1 p
= 1 u + 3
= 15 + 3
= 18

Number of lollipops that Perry bought
= 2 p
= 2 x 18
= 36

Answer(s): 36