A number increased by 371/2 % gives 33. The number is :

Answer: Option B

Let the number be x
Then,
$$\begin{array}{rl}& \left(100+37\frac{1}{2}\right)\%\text{of}x=33\\ & \Rightarrow 137\frac{1}{2}\%\text{of}x=33\\ & \Rightarrow \frac{275}{2}\times \frac{1}{100}\times x=33\\ & \Rightarrow x=\left(\frac{33\times 2\times 100}{275}\right)\\ & \Rightarrow x=24\end{array}$$