PSLE
Opal and Abi folded paper balls over two days. On Thursday, Opal folded 47 paper balls more than Abi. On Friday, Opal folded another 10 paper balls and Abi folded another 9. At the end of the two days, Opal made ⁷₁₀ of the total number of balls. What was the number of paper balls that Abi folded?

	Opal	Abi	Difference
Before	1 u + 47	1 u	47
Change	+ 10	+ 9
After	1 u + 57	1 u + 9	48
Comparing between Opal and Abi in the end	7 p	3 p	4 p

Difference between the number of paper balls that Opal and Abi folded in the end is repeated.

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

Difference between the number of paper balls that Opal and Abi folded in the end
= (1 u + 57) - (1 u + 9)
= 1 u + 57 - 1 u - 9
= 57 - 9
= 48

4 p = 48

1 p = 48 ÷ 4 = 12

Number of paper balls that Abi folded
= 3 p
= 3 x 12
= 36

Answer(s): 36