Archived Stumpers (with solutions)
STUMPER #1.8: TIME TEASERS
(Did you solve something differently? There's almost always more than one way to solve
a math problem. Sometimes there's even more than one correct solution!)
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1. Once Around
____At what time each day does the hour hand on an analog clock complete its first full circle?
* Solution
Noon. 2. Equal Parts
____Use two lines to divide the the clock’s face into three parts, so that
the sum of the numbers in each of those three parts is the same.
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3. Bridge Crossing
__ Four people need to cross a bridge on a dark night. They have only one flashlight for the group. No more than two can cross at a time, and no one can cross unless one member of their group has a flashlight. A group can never cross faster than its slowest member. Annie can cross in one minute; Bob can cross in 2 minutes; Claire can cross in 5 minutes; and Doug can cross in 10 minutes. How can the whole group get to the other side in exactly 17 minutes?
* Solution
Annie and Bob cross together (2 minutes); Bob goes back (2 minutes); Claire and Doug cross together (10 minutes); Annie goes back (1 minute). Annie and Bob cross together (2 minutes) for a total of 17 minutes. _
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