PSLE
Roshel and Cathy folded paper balls over two days. On Wednesday, Roshel folded 35 paper balls more than Cathy. On Thursday, Roshel folded another 16 paper balls and Cathy folded another 9. At the end of the two days, Roshel made ⁵₇ of the total number of balls. What was the number of paper balls that Cathy folded?

	Roshel	Cathy	Difference
Before	1 u + 35	1 u	35
Change	+ 16	+ 9
After	1 u + 51	1 u + 9	42
Comparing between Roshel and Cathy in the end	5 p	2 p	3 p

Difference between the number of paper balls that Roshel and Cathy folded in the end is repeated.

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

Difference between the number of paper balls that Roshel and Cathy folded in the end
= (1 u + 51) - (1 u + 9)
= 1 u + 51 - 1 u - 9
= 51 - 9
= 42

3 p = 42

1 p = 42 ÷ 3 = 14

Number of paper balls that Cathy folded
= 2 p
= 2 x 14
= 28

Answer(s): 28