Question

when 6 boys were admitted and 6 girls left ,the percentage of boys increased from 60% to 75% .find the original number of boys and girls in the class

Answer 1

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Let the number of boys and girls be x and y respectively.
Percentage of boys = 60%.
⇒ x / (x + y) = 60/100
⇒ 100 x = 60x + 60y
⇒ 40 x - 60 y  = 0 ....(1)
6 boys were admitted ⇒ number of boys = (x + 6)
Percentage of boys = 75%
⇒ (x + 6) / (x + 6)+(y - 6) = 75/100
⇒ x - 3y = -2..... (2)
Solving equations (1)and (2), we get,
x = 24, y = 16.
Ans-:Therefore, original number of boys and girls are 24 and 16

Answer 2

Step-by-step explanation:

let the number of boys be x

let the number of girls be y

ACCORDING TO THE QUESTION

no.of boys /total no.of girls and boys=x/x+y=%of boys

%of boys is 60

x/x+y=60/100

100x=60x+60y

40x-60y=0.........(1)

%of boys increased=75

x+6/(x+6)(y-6)=75/100

x-3y=-2..........(2)

solving (1)and(2) we get

x=24,y=16

no.of boys=24

no.of girls=16