soumya1989 wrote:

Yesterday, a certain school had an equal number of boys and girls. Today, 18 boys left the school, and the ratio of the number of boys to girls is now 3 to 4.

Column A | Column B |

Number of boys in the school now | 72 |

A)The quantity in Column A is greater.

B)The quantity in Column B is greater.

C)The two quantities are equal.

D)The relationship cannot be determined from the information given.

First of all, we should set the ratio in terms of scale factor for the numbers of boy to girls yesterday. That is \(\frac{a}{a}\) where the numerator stands for boy.

For today we can set that \(\frac{a-18}{a}\)=\(\frac{3}{4}\).

Then we cross multiply. We get 3a=4a-72, a=72. and today's boy number would be 72-18=54

Thus, B>A