Test Index

Ratio and Proportion

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Question : 35 of 112

Marks: +1, -0

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?

$8:9$
$17:18$
$21: 22$
Cannot be deterthined.

Solution:

Concept:

Ratios adjust with percentage changes; apply multipliers to initial ratio terms and simplify.

Explanation:

Assume initial number of boys =

7x

and girls =

8x

.

After a 20% increase, new boys =

7x \times 1.2 = 8.4x

.

After a 10% increase, new girls =

8x \times 1.1 = 8.8x

.

The new ratio is

8.4x : 8.8x

.

Remove

x

and simplify:

8.4 : 8.8

equals

84 : 88

after multiplying by 10.

Divide both by 4 to get

21 : 22

.

Answer:

21 : 22

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