SSC Quantitative Aptitude Ratio and Proportion Question Bank Ratio and Proportion (I)

In a college union, there are 48 students. The ratio of the number of boys to the number of girls is 5 : 3. The number of girls to be added in the union, so that the number of boys to girls in 6 : 5, is [SSC CGL Tier II, 2017]

A) 6

B) 7

C) 12

D) 17

Correct Answer: B

Solution :

[b] Let, number of boys in union\[=5x\]

and number of girls in union \[=3x\]

According to the question,

\[5x+3x=48\]\[\Rightarrow \]\[8x=48\]\[\Rightarrow \]\[x=6\]

\[\therefore \]Number of boys \[=5x=5\times 6=30\]

Number of girls \[=3x=3\times 6=18\]

Let, G girls should be added to make the ratio of 6 : 5.

According to the question, \[\frac{30}{18+G}=\frac{6x}{5x}=\frac{6}{5}\]

\[\Rightarrow \] \[(18+G)\times 6=5\times 30\]\[\Rightarrow \]\[18+G=25\]

\[\Rightarrow \] \[G=25-18=7\]\[\Rightarrow \]\[G=7\]