AMC 8 1989 Problem 9

There are $2$ boys for every $3$ girls in Ms. Johnson's math class. If there are $30$ students in her class, what percent of them are boys? $\text{(A)}\ 12\% \text{(B)}\ 20\% \text{(C)}\ 40\% \text{(D)}\ 60\% \text{(E)}\ 66\frac{2}{3}\%$