Fun with Fuses...
With only two fuses that burn exactly one hour, one
can measure three quarters of an hour accurately, by lighting the first
fuse at both ends and the other fuse at one end simultaneously.
When the first fuse is burnt out after exactly half an hour (!) you
know that the second fuse still has exactly half an hour to go before
it will be burnt completely, but we won't wait for that. We will now
also light the other end of the second fuse. This means that the second
fuse will now be burnt completely after another quarter of an hour,
which adds up to exactly three quarters of an hour since we started
lighting the first fuse!
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