PSLE
Vanessa and Mary folded paper stars over two days. On Wednesday, Vanessa folded 17 paper stars more than Mary. On Thursday, Vanessa folded another 17 paper stars and Mary folded another 7. At the end of the two days, Vanessa made ⁵₇ of the total number of stars. What was the number of paper stars that Mary folded?

	Vanessa	Mary	Difference
Before	1 u + 17	1 u	17
Change	+ 17	+ 7
After	1 u + 34	1 u + 7	27
Comparing between Vanessa and Mary in the end	5 p	2 p	3 p

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

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

Difference between the number of paper stars that Vanessa and Mary folded in the end
= (1 u + 34) - (1 u + 7)
= 1 u + 34 - 1 u - 7
= 34 - 7
= 27

3 p = 27

1 p = 27 ÷ 3 = 9

Number of paper stars that Mary folded
= 2 p
= 2 x 9
= 18

Answer(s): 18