PSLE
Kathy bought some lollipops and gave half of it to Cody. Cody bought some sweets and gave half of it to Kathy. Kathy ate 4 sweets and Cody ate 34 lollipops. The ratio of Kathy's sweets to lollipops became 1 : 5 and the ratio of Cody's sweets to lollipops became 1 : 2. How many lollipops did Kathy buy?

	Kathy		Cody
	Sweets	Lollipops	Sweets	Lollipops
Before	1 u + 4	5 u	1 p	2 p + 34
Change	- 4			- 34
After	1 u	5 u	1 p	2 p

After Kathy gave half of the lollipops to Cody and Cody gave half of his sweets to Kathy, Cody and Kathy had same number of sweets and lollipops before each ate some.

5 u = 2 p + 34 
5 u - 34 = 2 p --- (1)

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

Make p the same.

(2)_x2
2 u + 8 = 2 p --- (3)

(1) = (3)
5 u - 34 = 2 u + 8 
5 u - 2 u = 8 + 34
3 u = 42

1 u = 42 ÷ 3 = 14

Number of lollipops that Kathy bought
= 2 x 5 u
= 10 u
= 10 x 14
= 140

Answer(s): 140