The ratio of the number of boys and girls in a college is 7 : 8. If the percentage increase in the number of boys and girls be 20% and 10% respectively, what will be the new ratio?

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Question:
The ratio of the number of boys and girls in a college is 7 : 8. If the percentage increase in the number of boys and girls be 20% and 10% respectively, what will be the new ratio?

[A].

8 : 9

[B].

17 : 18

[C].

21 : 22

[D].

Cannot be determined

Answer: Option C

Explanation:

Originally, let the number of boys and girls in the college be 7x and 8x respectively.

Their increased number is (120% of 7x) and (110% of 8x).

120 x 7x and 110 x 8x
100 100
42x and 44x
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The required ratio = 42x : 44x = 21 : 22.
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