The number of girls enrolled in Arts, Science and Commerce forms what percent of total number of students in the college?

Answer: Option E

Number of students enrolled in various streams:
$$\begin{array}{rl}& \text{IT → }\frac{20}{100}\times 3500=700\\ & \text{Arts → }\frac{30}{100}\times 3500=1050\\ & \text{Science → }\frac{22}{100}\times 3500=770\\ & \text{Commerce → }\frac{12}{100}\times 3500=420\\ & \text{Management → }\frac{16}{100}\times 3500=560\end{array}$$

Number of girls enrolled in various streams:
$$\begin{array}{rl}& \text{IT → }\frac{18}{100}\times 1500=270\\ & \text{Arts → }\frac{38}{100}\times 1500=570\\ & \text{Science → }\frac{11}{100}\times 1500=165\\ & \text{Commerce → }\frac{21}{100}\times 1500=315\\ & \text{Management → }\frac{12}{100}\times 1500=180\end{array}$$

Number of girls enrolled in Arts, Science and Commerce
  = 570 + 165 + 315
  = 1050
Required percentage
$$\begin{array}{rl}& =\left(\frac{1050}{3500}\times 100\right)\%\\ & =30\%\end{array}$$