PSLE
Marion and Hilda folded paper cranes over two days. On Saturday, Marion folded 39 paper cranes more than Hilda. On Sunday, Marion folded another 10 paper cranes and Hilda folded another 9. At the end of the two days, Marion made ⁷₁₀ of the total number of cranes. What was the number of paper cranes that Marion folded?

	Marion	Hilda	Difference
Before	1 u + 39	1 u	39
Change	+ 10	+ 9
After	1 u + 49	1 u + 9	40
Comparing between Marion and Hilda in the end	7 p	3 p	4 p

Difference between the number of paper cranes that Marion and Hilda folded in the end is repeated.

Difference between the number of paper cranes that Marion and Hilda folded in the end
= 7 p - 3 p
= 4 p

Difference between the number of paper cranes that Marion and Hilda folded in the end
= (1 u + 49) - (1 u + 9)
= 1 u + 49 - 1 u - 9
= 49 - 9
= 40

4 p = 40

1 p = 40 ÷ 4 = 10

Number of paper cranes that Marion folded
= 7 p
= 7 x 10
= 70

Answer(s): 70