The world's population is over 6 billion people. A estimate of 1/6 of them celebrate Christmas. Santa works from midnight until 6:00am. How much time does Santa have to visit each house? How many houses must he visit each second? Allow for 4 people per household and 24 time zones.

Answer 1

By going from east to west, Santa gets to cross time zone boundaries and set his watch back one hour 24 times. Therefore he has 24+6 = 30 hours of real elapsed time to accomplish his mission. To visit 1 billion Christmas-observing people in 30 hours, thatr means 10^9/(30*60*60) = 9260 people (2315 houses) per second.