How Many Girls are There in the Class?

In a class, the number of boys and girls is in the ratio of 4:5. If 10 more boys join the class, the ratio of numbers of boys and girls becomes 6:5. How many girls are there in the class?

  1. 20
  2. 30
  3. 25
  4. None of these
Anurag Mishra Professor Asked on 29th July 2015 in Maths.
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1 Answer(s)
Best answer

Answer: (3) 25 girls
Explanation:-
Let the number of boys 4 X & the number of girls  = 5 X
According to the question,
(4 X + 10) /5 X = 6/5
5 x (4 X + 10) = 6 x 5 X
20 X + 50 = 30 X
30 X – 20 X = 50
10 X = 50
X = 50/10
X = 5
Then, the number of girls in the class = 5 X = 5 x 5 = 25.
Hence, the answer is (3) 25 girls.

Anurag Mishra Professor Answered on 29th July 2015.
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