Question

In a co-educational school there are 2800 students. if in a year, the number of boys were to increase by 5% and that of girls by 10%, the school would have 3000 students. Find the original number of boys and girls studying in the school.

Answer 1

(5x/100)+(10y/100)=200
=> 5x+10y=20000
=> x+2y=4000 -(1)
x+y=2800 -(2)
=> 0+y=1200 (on substraction)
x=2800-1200=1600
Therefore, no. of boys= 1600
and no. of girls = 1200.

Answer 2

Concept

Percentage concept can be used to indicate change in certain quantity.

Given

There are total of 2800 students in the school , In a year boys will increase by 5% and girls increase by 10% changing total to 3000 students.

Find

The original number of boys and girls studying in the school.

Solution

Let number of boys be 'x' and number of girls be 'y' ,  then according to the question

(5x+/100)+(10y/100) = 200

⇒ 5x+10y=20000

⇒ x+2y=4000...........(1)

Also x+y+2800.........(2)

subtracting both the equations ,

y=1200

then x = 2800-1200 ,

⇒ x = 1600

Hence the number of boys and girls are 1600 and 1200 respectively.

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