PSLE
Opal and Dana folded paper cranes over two days. On Friday, Opal folded 36 paper cranes more than Dana. On Saturday, Opal folded another 13 paper cranes and Dana folded another 21. At the end of the two days, Opal made ⁵₈ of the total number of cranes. What was the number of paper cranes that Opal folded?

	Opal	Dana	Difference
Before	1 u + 36	1 u	36
Change	+ 13	+ 21
After	1 u + 49	1 u + 21	28
Comparing between Opal and Dana in the end	5 p	3 p	2 p

Difference between the number of paper cranes that Opal and Dana folded in the end is repeated.

Difference between the number of paper cranes that Opal and Dana folded in the end
= 5 p - 3 p
= 2 p

Difference between the number of paper cranes that Opal and Dana folded in the end
= (1 u + 49) - (1 u + 21)
= 1 u + 49 - 1 u - 21
= 49 - 21
= 28

2 p = 28

1 p = 28 ÷ 2 = 14

Number of paper cranes that Opal folded
= 5 p
= 5 x 14
= 70

Answer(s): 70