PSLE
Kimberly and Cindy folded paper balls over two days. On Friday, Kimberly folded 18 paper balls more than Cindy. On Saturday, Kimberly folded another 19 paper balls and Cindy folded another 1. At the end of the two days, Kimberly made ⁵₇ of the total number of balls. What was the number of paper balls that Cindy folded?

	Kimberly	Cindy	Difference
Before	1 u + 18	1 u	18
Change	+ 19	+ 1
After	1 u + 37	1 u + 1	36
Comparing between Kimberly and Cindy in the end	5 p	2 p	3 p

Difference between the number of paper balls that Kimberly and Cindy folded in the end is repeated.

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

Difference between the number of paper balls that Kimberly and Cindy folded in the end
= (1 u + 37) - (1 u + 1)
= 1 u + 37 - 1 u - 1
= 37 - 1
= 36

3 p = 36

1 p = 36 ÷ 3 = 12

Number of paper balls that Cindy folded
= 2 p
= 2 x 12
= 24

Answer(s): 24