Find the Number of Boys Who Left the School :

In a school there were 1554 students and the ratio of the number of the boys and girls was 4:3. After few days, 30 girls joined the school but few boys left: as a result the ratio of the boys and girls became 7:6. The number of boys who left the school?

  1. 86
  2. 76
  3. 84
  4. 74
Anurag Mishra Professor Asked on 26th October 2015 in Maths.
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1 Answer(s)

Answer is (2): 76

Explanation:-
The total number of students in a school = 1554
The ratio of the number of boys and girls = 4: 3

Then, the number of boys in a school= 1554 x 4/7
 = 222 x 4
 = 888
And the number of girls in the school = 1554 x 3/7
 = 222 x 3 
 = 666

After few days, 30 girls joined the school but few boys left
Then, the number of girls = 666 + 30
 = 696

Then, the new ratio of boys and girls = 7: 6
Let the number of boys be = 7 X and the number of girls be = 6 X
Then, 6 X = 696
 X = 696/6
 X = 116

So, the number of boys = 116 x 7
 = 812

Then, the number of boys who left the school = 888 – 812
 = 76

Hence, the answer is (2) 76.

Monis Rasool Professor Answered on 28th October 2015.
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