Question

In a class of $21$ students, the ratio of girls to boys is $4:3$. How many girls are there in the class?

• A. $8$
• B. $9$
• C. $7$
• D. $12$

Answer 1

The correct option is D $12$

Let number of boys be $x$ and number of girls be $y$,

Then it is given that

Given, $x+y=21$

Also given $\frac{x}{y}=\frac{4}{3}$

$\Rightarrow x=\frac{4y}{3}$

Substituting $2^{nd}$ equation in $1^{st}$, we get,

$\frac{4y}{3}+y=21$

$\Rightarrow 7y=63$

$\Rightarrow y=9$

Therefore, $x=21-9=12$