Question

The ratio of the number of boys and the girls is \[4:3\]. If there are 18 girls in a class, then find the total number of students in the class.
A.40
B.41
C.42
D.43

Answer 1

Hint: We are given the ratio of the number of boys and the girls and the number of girls. First, we’ll assume a variable for the number of boys and substituting that in the given ratio we’ll get the number of boys.
Now, we know that the total number of students is equal to the sum of the number of boys and the number of girls so on adding these values we’ll get our answer.

Complete step-by-step answer:
Given data: The ratio of the number of boys and girls is \[4:3\]
The number of girls=18
Let the number of boys be B
According to the given data, boys to girls ratio is \[4:3\]
i.e. $\dfrac{B}{{18}} = \dfrac{4}{3}$
On rearranging we get,
$ \Rightarrow B = \dfrac{4}{3}\left( {18} \right)$
On simplifying we get,
$ \Rightarrow B = 4\left( 6 \right)$
$\therefore B = 24$
It is well known that the total number of students in the class is equal to the sum of the number of boys and the number of girls.
\[The{\text{ }}total{\text{ }}number{\text{ }}of{\text{ }}students = 18 + 24\]
Hence, Total number of students is 42.
Option(C) is the correct option.

Note: Alternative way to find the total number of students can be
We can say that the number of boys is equal to the difference between the total number of students let’s say ‘N’ and the number of girls
According to the ratio given
i.e. $\dfrac{{N - 18}}{{18}} = \dfrac{4}{3}$
On simplification we get,
$ \Rightarrow N - 18 = \dfrac{4}{3}(18)$
$ \Rightarrow N = 24 + 18$
$\therefore N = 42$
From both the methods the total number of students is 42.
i.e. option(C) 42