PSLE
Irene and Kathy folded paper cranes over two days. On Thursday, Irene folded 13 paper cranes more than Kathy. On Friday, Irene folded another 33 paper cranes and Kathy folded another 1. At the end of the two days, Irene made ⁵₇ of the total number of cranes. What was the number of paper cranes that Kathy folded?

	Irene	Kathy	Difference
Before	1 u + 13	1 u	13
Change	+ 33	+ 1
After	1 u + 46	1 u + 1	45
Comparing between Irene and Kathy in the end	5 p	2 p	3 p

Difference between the number of paper cranes that Irene and Kathy folded in the end is repeated.

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

Difference between the number of paper cranes that Irene and Kathy folded in the end
= (1 u + 46) - (1 u + 1)
= 1 u + 46 - 1 u - 1
= 46 - 1
= 45

3 p = 45

1 p = 45 ÷ 3 = 15

Number of paper cranes that Kathy folded
= 2 p
= 2 x 15
= 30

Answer(s): 30