PSLE
Cathy and Sarah folded paper cranes over two days. On Monday, Cathy folded 20 paper cranes more than Sarah. On Tuesday, Cathy folded another 28 paper cranes and Sarah folded another 6. At the end of the two days, Cathy made ⁵₇ of the total number of cranes. What was the number of paper cranes that Sarah folded?

	Cathy	Sarah	Difference
Before	1 u + 20	1 u	20
Change	+ 28	+ 6
After	1 u + 48	1 u + 6	42
Comparing between Cathy and Sarah in the end	5 p	2 p	3 p

Difference between the number of paper cranes that Cathy and Sarah folded in the end is repeated.

Difference between the number of paper cranes that Cathy and Sarah folded in the end
= 5 p - 2 p
= 3 p

Difference between the number of paper cranes that Cathy and Sarah folded in the end
= (1 u + 48) - (1 u + 6)
= 1 u + 48 - 1 u - 6
= 48 - 6
= 42

3 p = 42

1 p = 42 ÷ 3 = 14

Number of paper cranes that Sarah folded
= 2 p
= 2 x 14
= 28

Answer(s): 28