Solution to April’s Puzzle:
Suicidal Mosquito
Two trains drive toward each other on the same rail.
Both trains drive at a speed of 100MPH. When the
trains are 100 miles apart, a mosquito starts flying
back and forth from the front of one train to the
other at a speed of 200MPH. What total distance
will the mosquito cover before the two trains crash?
For some people the puzzle might seem to
require infinity calculations. Although solving the
puzzle this way is possible, such a solution is
unnecessarily complicated. The simplest way to
think about the puzzle is to consider only duration
and speed. The time it takes until the trains crash
is half an hour, and the speed of the mosquito is
200MPH. With such speed and duration, the mosquito
would cover 100 miles.
May’s Puzzle: A Cat, a String,
and the Earth
This month’s puzzle is quite simple, but I like it
because it’s so counter intuitive. Suppose you lay a
string on the ground all around the earth right over
the equator. The length of the string would be equal
to the earth’s equatorial circumference—40,075.02
kilometers. Then, suppose you add 1 meter to the
string, and suspend the string directly above the
equator, with an even distance from the ground all
the way around. Would a cat be able to pass from
one hemisphere to another below the string?
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