Question

If a numerator of a certain fraction is increased by 100% and the denominator is increased by 200% the new fraction thus formed is 4/21 .
What is the original fraction..
:2/7
:3/7
:2/5
:4/7
:none..

Answer 1

the original fraction is

4 ÷ 200 × 100
-------------------
21 ÷ 300 × 100

= 2/7 ..

Answer 2

Given :

If a numerator of a certain fraction is increased by 100% and the denominator is increased by 200% the new fraction thus formed is 4/21 .

To Find:

The new fraction thus formed is 4/21 .

Solution:

Let the numerator be x and denominator  be y

Fraction = \frac{x}{y}

Increased numerator = x+100\%x=2x

Increased denominator = y+200\%y=3y

So, New fraction = \frac{2x}{3y}

we are given that the new fraction thus formed is 4/21 .

So, $\frac{2x}{3y}=\frac{4}{21}\\\frac{x}{y}=\frac{4 \times 3}{21 \times 2}\\\frac{x}{y}=\frac{2}{7}$

Hence The original fraction is 2/7