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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?

A) 20
B) 30
C) 25
D) Couldn't be determined

Correct Answer:



C) 25

Description for Correct answer:
Let original number of boys = 4x and number of girls = 5x

According to the question,

\( \Large \frac{4x+10}{5x}=\frac{6}{5} \)

=> 30x = 20x + 50

=> 10x = 50

x=\( \Large \frac{50}{10} \) = 5

Number of girls = 5X = 5x5 = 25

Part of solved Ratio and Proportions questions and answers : >> Aptitude >> Ratio and Proportions

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