A library has an average of 510 visitors on Sunday and 240 on other days. The average number of visitors per day in a month of 30 days beginning with a Sunday is Select the correct option:
A) 250
B) 276
C) 280
D) 285
E) None
Sol.   Since the month begins with a Sunday, so there will be five Sundays in the month.   ∴ Required average = [510 x 5 + 240 x 25 / 30] = 8550 / 30= 
<gadget id="calculator">8550 / 30</gadget>
<output>285</output>
285   Answer 285
<result>D</result>
A library has an average of 510 visitors on Sunday and 240 on other days. The average number of visitors per day in a month of 30 days beginning with a Sunday is