A library has an average of 510 visitors on Sundays and 240 on other days. The average number of visitors per day in a month of 30 days beginning with a Sunday is-

Answer: Option D

Since the month begins with a Sunday, so there will be five Sundays in the month.
∴ Required average
$$\begin{array}{rl}& =\left(\frac{510\times 5+240\times 25}{30}\right)\\ & =\frac{8550}{30}\\ & =285\end{array}$$