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
Solution(By Examveda Team)
Originally, let the number of boys and girls in the college be 7x and 8x respectivelyTheir increased number is (120% of 7x) and (110% of 8x)
$$\eqalign{ & \Rightarrow \left( {\frac{{120}}{{100}} \times 7x} \right)\,{\text{and}}\,\left( {\frac{{110}}{{100}} \times 8x} \right) \cr & \Rightarrow \frac{{42x}}{5}\,{\text{and}}\,\frac{{44x}}{5} \cr & \therefore {\text{The}}\,{\text{required}}\,{\text{ration}} \cr & = {\frac{{42x}}{5}:\frac{{44x}}{5}} \cr & = 21:22 \cr} $$
This Question Belongs to Arithmetic Ability >> Ratio
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