Question

In a class, the number of girls is $20\%$ more than that of boys. The strength of the class is $66.$ If $4$ more girls are admitted to the class, then the ratio of the number of boys to that of girls is

• A. $1:2$
• B. $1:4$
• C. $3:4$
• D. $3:5$

Answer 1

The correct option is C $3:4$

Let the number of boys be $x.$
Then, number of girls $=x+\frac{20}{100}x=\frac{6x}{5}$
$\therefore x+\frac{6x}{5}=66$
$\Rightarrow \frac{11x}{5}=66$
$\Rightarrow x=\frac{66\times 5}{11}=30$
So, the number of boys $=30$
and, new number of girls $=\left(\frac{6\times 30}{5}\right)+4=40$
$\therefore$ Required ratio $=30:40=3:4$