A public library has an average attendance of 410 on Sundays and 230 for the remaining days. The average attendance per day of a month of 30 days beginning with Sunday would be:

Correct option is D

Given:
Average attendance on Sundays = 410
Average attendance on other days = 230
Total days in a month = 30 days, starting with Sunday
Formula Used:
​$$\text{Average} = \frac{\text{Total sum of the values}}{\text{Total number of values}}$$​​
Solution:
If a 30-days month is starting with Sunday, so a total of 5 Sundays will occur in the month.
Attendance on total 5 Sundays = 410 × 5 = 2050
Attendance on rest 25 days = 230 × 25 = 5750
Total attendance in 30-days month = 2050 + 5750 = 7800
Average attendance for the whole month = $$\frac{7800}{30}=260$$​​