You may also like
Speedy Sidney
Two trains set off at the same time from each end of a single straight railway line. A very fast bee starts off in front of the first train and flies continuously back and forth between the two trains. How far does Sidney fly before he is squashed between the two trains?
Rule of Three
If it takes four men one day to build a wall, how long does it take 60,000 men to build a similar wall?
Digital Times
Which segment on a digital clock is lit most each day? Which segment is lit least? Does it make any difference if it is set to 12 hours or 24 hours?
Age 11 to 14
Challenge Level
It is believed that this problem was invented by Edouard Lucas and that he also invented the well known Frogs problem. He was a French mathematician who lived in the nineteenth century.
Every day at noon (Greenwich Mean Time) a boat leaves Le Havre
for New York while another boat leaves New York for Le Havre.
The ocean crossing takes seven days and seven nights.
How many boats on the New York to Le Havre route will the boat
leaving Le Havre today meet during its journey to New York?
Does it change your answer if the boats leave Le Havre and New York
at noon local time. How can you illustrate your answer?
NRICH is part of the family of activities in the Millennium Mathematics Project.