PSLE
Dana and Kathy folded paper stars over two days. On Monday, Dana folded 42 paper stars more than Kathy. On Tuesday, Dana folded another 37 paper stars and Kathy folded another 4. At the end of the two days, Dana made ⁷₉ of the total number of stars. What was the number of paper stars that Kathy folded?

	Dana	Kathy	Difference
Before	1 u + 42	1 u	42
Change	+ 37	+ 4
After	1 u + 79	1 u + 4	75
Comparing between Dana and Kathy in the end	7 p	2 p	5 p

Difference between the number of paper stars that Dana and Kathy folded in the end is repeated.

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

Difference between the number of paper stars that Dana and Kathy folded in the end
= (1 u + 79) - (1 u + 4)
= 1 u + 79 - 1 u - 4
= 79 - 4
= 75

5 p = 75

1 p = 75 ÷ 5 = 15

Number of paper stars that Kathy folded
= 2 p
= 2 x 15
= 30

Answer(s): 30