PSLE
Mary and Irene folded paper stars over two days. On Friday, Mary folded 37 paper stars more than Irene. On Saturday, Mary folded another 15 paper stars and Irene folded another 13. At the end of the two days, Mary made ⁵₇ of the total number of stars. What was the number of paper stars that Mary folded?

	Mary	Irene	Difference
Before	1 u + 37	1 u	37
Change	+ 15	+ 13
After	1 u + 52	1 u + 13	39
Comparing between Mary and Irene in the end	5 p	2 p	3 p

Difference between the number of paper stars that Mary and Irene folded in the end is repeated.

Difference between the number of paper stars that Mary and Irene folded in the end
= 5 p - 2 p
= 3 p

Difference between the number of paper stars that Mary and Irene folded in the end
= (1 u + 52) - (1 u + 13)
= 1 u + 52 - 1 u - 13
= 52 - 13
= 39

3 p = 39

1 p = 39 ÷ 3 = 13

Number of paper stars that Mary folded
= 5 p
= 5 x 13
= 65

Answer(s): 65