PSLE
Shiyun and Emily folded paper balls over two days. On Friday, Shiyun folded 40 paper balls more than Emily. On Saturday, Shiyun folded another 27 paper balls and Emily folded another 7. At the end of the two days, Shiyun made ⁷₉ of the total number of balls. What was the number of paper balls that Emily folded?

	Shiyun	Emily	Difference
Before	1 u + 40	1 u	40
Change	+ 27	+ 7
After	1 u + 67	1 u + 7	60
Comparing between Shiyun and Emily in the end	7 p	2 p	5 p

Difference between the number of paper balls that Shiyun and Emily folded in the end is repeated.

Difference between the number of paper balls that Shiyun and Emily folded in the end
= 7 p - 2 p
= 5 p

Difference between the number of paper balls that Shiyun and Emily folded in the end
= (1 u + 67) - (1 u + 7)
= 1 u + 67 - 1 u - 7
= 67 - 7
= 60

5 p = 60

1 p = 60 ÷ 5 = 12

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

Answer(s): 24