The total frequency is $50+60+40+60+40=250$, with the blue frequency of $60$. Therefore, the precentage that preferred blue is $\frac{60}{250}=\boxed{\text{(B)}\ 24\%}$.
The bar graph shows the results of a survey on color preferences.  What percent preferred blue?

$\text{(A)}\ 20\% \qquad \text{(B)}\ 24\% \qquad \text{(C)}\ 30\% \qquad \text{(D)}\ 36\% \qquad \text{(E)}\ 42\%$