PSLE
At first, Irene had an equal number of pink and black marbles . She gave away ³₄ of her pink marbles and some black marbles. In the end, she was left with ¹₄ of her marbles. What fraction of the black marbles did Irene give away?

	Pink	Black	Total
Comparing pink marbles and black marbles at first	1x4x1 = 4 u	1x4x1 =  4 u	2x4x1 =  8 u
Before	4x1 = 4 u	4 u	4x2 = 8 u
Change	- 3x1 = - 3 u	- 3 u	- 1x2 = - 6 u
After	1x1 = 1 u	1 u	3x2 = 2 u

After1_x1 =
1 u
1 u3_x2 =
2 u
The number of pink marbles at first is repeated. Make the number of pink marbles the first the same. LCM of 4 and 1 is 4.

The total number of marbles at first is repeated. Make the total number of marbles at first the same. LCM of 8 and 4 is 8.

Number of black marbles that Irene was left with
= 2 u - 1 u
= 1 u

Number of black marbles that Irene gave away
= 4 u - 1 u
= 3 u

Fraction of the black marbles that Irene gave away = ³₄

Answer(s): ³₄