1985 AJHSME Problem 16

Problem

The ratio of boys to girls in Mr. Brown's math class is $2:3$. If there are $30$ students in the class, how many more girls than boys are in the class?

$\text{(A)}\ 10 \qquad \text{(B)}\ 5 \qquad \text{(C)}\ 3 \qquad \text{(D)}\ 6 \qquad \text{(E)}\ 2$

In-depth Solution by BoundlessBrain!

https://youtu.be/LWBB5i_kmwE

Solution

If there are $30$ students in the class, there are $\frac{2}{2+3} \cdot 30 = 12$ boys and $\frac{3}{2+3} \cdot 30 = 18$ girls. So, there are $\boxed{\text{(D)} 6}$ more girls than boys.