PSLE
Usha and Risa folded paper stars over two days. On Tuesday, Usha folded 24 paper stars more than Risa. On Wednesday, Usha folded another 17 paper stars and Risa folded another 1. At the end of the two days, Usha made ⁷₉ of the total number of stars. What was the number of paper stars that Risa folded?

	Usha	Risa	Difference
Before	1 u + 24	1 u	24
Change	+ 17	+ 1
After	1 u + 41	1 u + 1	40
Comparing between Usha and Risa in the end	7 p	2 p	5 p

Difference between the number of paper stars that Usha and Risa folded in the end is repeated.

Difference between the number of paper stars that Usha and Risa folded in the end
= 7 p - 2 p
= 5 p

Difference between the number of paper stars that Usha and Risa folded in the end
= (1 u + 41) - (1 u + 1)
= 1 u + 41 - 1 u - 1
= 41 - 1
= 40

5 p = 40

1 p = 40 ÷ 5 = 8

Number of paper stars that Risa folded
= 2 p
= 2 x 8
= 16

Answer(s): 16