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?	Choose the correct choice from the following choices:
A) 8 : 9
B) 17 : 18
C) 21 : 22
D) 25 : 22
E) Cannot be determined
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).   =&gt;(120/100 X 7X) and (110/100 x 8x)   The required ratio =(42x/5 :44x /5)=21:22.   ANSWER IS 21 : 22
<result>C</result>
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?