A classroom contained an equal number of boys and girls . 8 girls left to play hockey, leaving twice as many boys as girls in class room.What was the original number of students present ?

3 Answers | Add Yours

william1941's profile pic

william1941 | College Teacher | (Level 3) Valedictorian

Posted on

Let the number of students originally be N. Now we know that there were an equal number of girls and boys.

Therefore number of girls = number of boys = N/2

When 8 girls left the class, the number of girls was N/2 - 8.

Now there were twice as many boys as girls.

Therefore (N/2 - 8)*2 = N/2

=> (N/2)*2 - 16 = N/2

=> N - 16 = N/2

=> N/2 = 16

=> N = 32

Therefore the number of students in the class was 32.

neela's profile pic

neela | High School Teacher | (Level 3) Valedictorian

Posted on

Since the number of girls and boys of the class are equal, we assume that they are x each . Therefore the total students of the class is 2x.

After 8 girls leave for hocky, the left out number of girls = x-8. Now the number boys are 2 times the number of left out girls. So x = 2(x-8).

x = 2x-16.

To solve the above equation we add 16 and subtract x from both sides.

x+16-x  = 2x-16+16-x

16 = x.

Therefore x = 16 . So the number of girls = number of boys  = 16

Therefore the total students of the class = 2x = 2*16 = 32.

giorgiana1976's profile pic

giorgiana1976 | College Teacher | (Level 3) Valedictorian

Posted on

We'll put the number of boys or girls as x.

If 8 girls left to play hockey, the total number of students is:

x-8

The number of boys is twice the number of girls:

2(x-8) = x

We'll remove the brackets and we'll get:

2x - 16 = x

We'll subtract x both sides and we'll add 16 both sides:

x = 16

The number of boys is 16 and the number of girls is also 16.

Initially, the total number of students present in classroom is:

16+16 = 32.

We’ve answered 318,982 questions. We can answer yours, too.

Ask a question