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:

Problem Restatement

Find the overall daily average visitors in a 30-day month starting on a Sunday, given different averages for Sundays and other days.

Given data

• Average on Sundays = 510
• Average on other days = 240
• Month length = 30 days, starts on Sunday

Concept / Approach

A 30-day month starting on Sunday has exactly 5 Sundays (days 1, 8, 15, 22, 29). The remaining 25 days are non-Sundays. Compute the total visitors using these counts, then divide by 30.

Step-by-step calculation

Number of Sundays = 5; Number of other days = 30 − 5 = 25Total visitors = 5 × 510 + 25 × 240= 2550 + 6000 = 8550Average per day = 8550 ÷ 30 = 285

Common pitfalls

• Assuming 4 or 6 Sundays without checking the start day.
• Averaging 510 and 240 directly (must weight by counts of days).

Final Answer

Average visitors per day for the month = 285.