ratio of boys to girls in a school is 4:5. if 100 girls leave the school,the ratio becomes 6:7.find the number of boys in school
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Answered by
18
4x/(5x-100)=6/7
28x= 30x -600
600=30x-28x=2x
x=300
so the boys in past are = 4x=1200
girls are =5x=1500
are the incedent boys = 1200
girls=1400
and the ratio satisfies
28x= 30x -600
600=30x-28x=2x
x=300
so the boys in past are = 4x=1200
girls are =5x=1500
are the incedent boys = 1200
girls=1400
and the ratio satisfies
ankitbalmiki83:
thank you!!
Answered by
16
let the ratio is =x
than boys are=4x
than girls are=5x
by que 100 girls leave the school
than girls are (5x-100)
now ratio becomes = 6:7
let , 4x : (5x-100) = 6:7
4x/(5x-100) = 6/7
Cross multiply
28x = 30x-600
28x-30x = - 600
-2x = -600
x = -600/-2 = 300
than boys are=4x
than girls are=5x
by que 100 girls leave the school
than girls are (5x-100)
now ratio becomes = 6:7
let , 4x : (5x-100) = 6:7
4x/(5x-100) = 6/7
Cross multiply
28x = 30x-600
28x-30x = - 600
-2x = -600
x = -600/-2 = 300
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