PSLE
Roshel bought some lollipops and gave half of it to George. George bought some sweets and gave half of it to Roshel. Roshel ate 7 sweets and George ate 15 lollipops. The ratio of Roshel's sweets to lollipops became 1 : 6 and the ratio of George's sweets to lollipops became 1 : 3. How many sweets did George buy?

	Roshel		George
	Sweets	Lollipops	Sweets	Lollipops
Before	1 u + 7	6 u	1 p	3 p + 15
Change	- 7			- 15
After	1 u	6 u	1 p	3 p

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

6 u = 3 p + 15 
6 u - 15 = 3 p --- (1)

1 u + 7 = 1 p --- (2)

Make p the same.

(2)_x3
3 u + 21 = 3 p --- (3)

(1) = (3)
6 u - 15 = 3 u + 21 
6 u - 3 u = 21 + 15
3 u = 36

1 u = 36 ÷ 3 = 12

1 p
= 1 u + 7
= 12 + 7
= 19

Number of sweets that George bought
= 2 p
= 2 x 19
= 38

Answer(s): 38