Question

In a class of 35 students, the number of girls is two-fifth of the number of boys Find the number of girls in the class​

Answer 1

Answer:

let x=no.of girls in the class

let y=no.of boys in the class

x+y=35

x=2/5y

x-2/5y=0

y+2/5y=35

7/5y=35

y=35×5/7

y=25

then x=10

the no. of girls=10

Answer 2

Answer:

given : total no. of students in the class = 35

           No. of girls = 2/5 th of no.of boys

to find : total no.of girls in the class

Let no of boys be x ,then

total no. of students = no.of boys + no.of girls

                           35  = x + $(\frac{2}{5} \times x)$    -----------------(given)

on solving we get ,

                            35 = $\frac{5x + 2x}{5}$

                             175 = 7$x$

                              $x = \frac{175}{7}$

                              $x = 25$

thus , we get no .of boys i.e x = 25

no we can find no. of girls i.e $\frac{2x}{5}$  by substituting value of x

                   =   $\frac{2 \times 25}{5}$

                    =  $\frac{50}{5}$

                     = 10

hence there are 25 boys and 10 girls in class.