Madhya Pradesh Police Exam Model Paper 6

Given:
Number of total boys and girls $=540$
The ratio of boys and girls is $5:4$
The total number of girls increase $=20\%$
Explanation:
Let the proportional ratio = x
According to the question,
$5\mathit{x}+4\mathit{x}=540$
$\Rightarrow 9\mathit{x}=540$
$\Rightarrow \mathit{x}=60$
So Boys = 5x = 5 × 60 = 300
Girls $=4\mathit{x}=4\times 60=240$
Now,
Girls increase $=240\times 20\%=48$
Number of total girl $=240+48=288$
The new ratio of boys and girls $=300:288=25:24$
∴ The new ratio of boys and girls is $25:24$ .
Shortcut:
Given:
Number of total boys and girls = 540
The ratio of boys and girls is 5 : 4
The total number of girls increase = 20%
Explanation:
Number of boys $=540\times \left(5/9\right)=300$
Number of girls = 540 - 300 = 240
Number of girls after increase of $20\%=240\times 120\%=288$
The new ratio of boys and girls $=300:288=25:24$
∴ The new ratio of boys and girls is 25 : 24.