Chapter 6, Problem 14PFA

To determine

To find : To find the number of girls in the class.

Answer to Problem 14PFA

Number of girls in the class are 20.

So option A is correct.

Explanation of Solution

Given information :

Given total number of boys and girls in the class are 28.

And number of girls are 12 more than the number of boys in the class.

Suppose number of girls in the class are x .

And number of the boys in the class are y.

According to the question:

Number of girls in the class + Number of boys in the class= 28

  $x+y=28$ .... Equation 1

And

Number of girls in the class-Number of boys in the class= 12

  $x-y=12$ ......Equation 2

Adding both the equations, we get:

  $\begin{array}{l}(x+y)+(x-y)=28+12\\ \Rightarrow x+y+x-y=40\\ \Rightarrow 2x=40\\ \Rightarrow x=\frac{40}{2}\\ \Rightarrow x=20\end{array}$

So number of girls in the class are 20.

So option A is correct.