Latest Elitmus Aptitude Question SOLUTION: Ratio of boys to girls 4:5 , when 100 girls leave the school the ratio becomes 6:7 . How many boys are there ? a) 1600 b) 1200 c) 600 d) 800

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(#M40034632) ELITMUS Numerical Ability question Keep an EYE

Ratio of boys to girls 4:5 , when 100 girls leave the school the ratio becomes 6:7 . How many boys are there ?
a) 1600
b) 1200
c) 600
d) 800

Asked In Elitmus Pawan Pandey (10 years ago)

Solved RAKESH Read Solution (13)

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Read Solution (13) :

RAKESH  (10 years ago)

B/G = 4/5 => G = 5B/4 -----(1)

B/(G-100) = 6/7 ------(2)
=> 7B = 6G -600
=> 7B = 6*5B/4 -600
=> 28B = 30B -2400
=> 2B = 2400
=> B = 1200

b) 1200

Is this solution Helpfull? Yes (50) | No   

prabhat srivastava  (10 years ago)

ye bakwaas ques elitmus ka hai kya? elitmus ka standard kab se itana low ho gya ....

Is this solution Helpfull? Yes (19) | No (2)  

shree  (10 years ago)

answer is b)1200 .because only 1200 is divided in 1st radio by 4 and in 2nd radio by 6 so this is right answer.
and if we take 1200 for boys then in 1st condition girls are 1500 and in 2nd condition 1400.

Is this solution Helpfull? Yes (3) | No   

gagandeep singh  (10 years ago)

x/y = 4/5 => x=4/5*y.....(1)
now,
100 girls left so the new ratio became:
x/(y-100)=6/7 ...(2)
solving 1 & 2,
x=1200 so 1200 boys is the answer.

Is this solution Helpfull? Yes (1) | No   

TEJASWINI SATAPATHY  (10 years ago)

4x/(5x-100)=6:7
=>x=300
boys=4*300=1200

Is this solution Helpfull? Yes (1) | No   

mohan lal garg  (10 years ago)

boys=4x
girl=5x
4x/(5x-100)=6/7
x=300
girls=5*300=1500

Is this solution Helpfull? Yes | No (4)  

Ambe Pratap Singh  (9 years ago)

4x/5x-100 = 6/7
28x = 30x-600
x = 300
so boys = 4x = 4*300 = 1200

Is this solution Helpfull? Yes | No   

Saurav Kumar  (9 years ago)

Let number of boys and girls be x and y respectively.As given,x/y=4/5.now x/y-100=6/7.when we solve second equation we get y=1500.also from first equation we can say x=4y/5.Substituting the value of y=1500 in x=4y/5,we get x=1200 which is the number of boys.Therefore number of boys=1200.

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ravi prakash  (9 years ago)

1200

b/g=4/5;
b/g-100=6/7
on solving these two equation
we got b=1200

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Dark Knight  (9 years ago)

4x/5x-100=6/7
x=300
4*300=1200

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Dark Knight  (9 years ago)

1200/4=300
1200/6=200
difference is 100 hence answer is 1200. No other option provide you with a difference of 100

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chandini tadela  (8 years ago)

boys=4x
girls=5x
so
4x/5x-100=6/7
28x=30x-600
2x=600
so x=300
initially boys are 4x
sustitute 300 in x
so 4*300
1200

Is this solution Helpfull? Yes | No   

Mohd Jahid  (4 years ago)

Let boys be 4x and girls be 5x.
According to question.
4x / (5x -100) = 6/7.
On solving this we get x=300.
Then boys is 4*300 = 1200

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