PSLE
Zara and Cindy folded paper cranes over two days. On Friday, Zara folded 21 paper cranes more than Cindy. On Saturday, Zara folded another 40 paper cranes and Cindy folded another 1. At the end of the two days, Zara made ⁷₉ of the total number of cranes. What was the number of paper cranes that Zara folded?

	Zara	Cindy	Difference
Before	1 u + 21	1 u	21
Change	+ 40	+ 1
After	1 u + 61	1 u + 1	60
Comparing between Zara and Cindy in the end	7 p	2 p	5 p

Difference between the number of paper cranes that Zara and Cindy folded in the end is repeated.

Difference between the number of paper cranes that Zara and Cindy folded in the end
= 7 p - 2 p
= 5 p

Difference between the number of paper cranes that Zara and Cindy folded in the end
= (1 u + 61) - (1 u + 1)
= 1 u + 61 - 1 u - 1
= 61 - 1
= 60

5 p = 60

1 p = 60 ÷ 5 = 12

Number of paper cranes that Zara folded
= 7 p
= 7 x 12
= 84

Answer(s): 84