Question

in a school 3/5 of the students are girls. if the number of boys in the school is 200 , find the total number of students in the school?
Ans is 500 and I don't how it come

Answer 1

If 2/5 of the total number of students 
are girls, then the total of pupils
= 500 ((200*5)/2)

explanation---

Let the no. of students in the class be x.
Then 3/5x=girls.
x-3/5x=boys.
5x-3x/5=2x/5=boys.
no.of boys=200
2x/5=200
2x=200*5
x=1000/2
x=500
Total no. of stdents in the class are 500.

hope it helps

Answer 2

let the no. of students be x

then 3/5x+200=500

3/5x=500-200=300

x=300÷3/5
300×5/3 =500