PSLE
Gillian and Zoe folded paper balls over two days. On Thursday, Gillian folded 20 paper balls more than Zoe. On Friday, Gillian folded another 25 paper balls and Zoe folded another 5. At the end of the two days, Gillian made ⁷₁₀ of the total number of balls. What was the number of paper balls that Zoe folded?

	Gillian	Zoe	Difference
Before	1 u + 20	1 u	20
Change	+ 25	+ 5
After	1 u + 45	1 u + 5	40
Comparing between Gillian and Zoe in the end	7 p	3 p	4 p

Difference between the number of paper balls that Gillian and Zoe folded in the end is repeated.

Difference between the number of paper balls that Gillian and Zoe folded in the end
= 7 p - 3 p
= 4 p

Difference between the number of paper balls that Gillian and Zoe folded in the end
= (1 u + 45) - (1 u + 5)
= 1 u + 45 - 1 u - 5
= 45 - 5
= 40

4 p = 40

1 p = 40 ÷ 4 = 10

Number of paper balls that Zoe folded
= 3 p
= 3 x 10
= 30

Answer(s): 30