December 2023 Puzzler
December 01, 2023
This is a little bit of an unusual puzzler – I hope you enjoy it. What is the number of the parking space in which the red car is parked?
Solution to May Puzzler
The exact time is 49 and 1/11 seconds after 7:21.
Imagine the clock with 60 tick marks evenly spaced around the circular edge. We can label these marks from 1 to 60, with 60 being the top of the clock. Let's suppose the clock hands are perpendicular at X minutes after 7:00. Then the big hand is at position X, while the little hand must be at X+15 (since 90 degrees on the clock is 15 of the one-minute ticks). But the little hand was at position 35 at 7:00 and moves one tick every 12 minutes, so it is now at 35+(X/12). This gives us an equation:
35 + X/12 = X + 15
20 = (11/12)X
X = 240/11 = 21 and 9/11.
So, the hands are perpendicular at 21 minutes and (9/11)(60) = 49 and 1/11 seconds after 7:21.
Correct Solvers
First correct solution: Alex Blumenfeld, NMR Lab Manager, U of I Chemistry
Second correct Solution: Greg Stenback, B.S. Geological Engineering 1984, M.S. Statistics 1987
Others:
- Victor Afigbo
- Mark Daily, B.S. Physics 1981
- Duke Hughes, B.S. Chemistry 1961
- Ruprecht Machleidt, Professor, U of I Physics
- Brent Morris, B.S. Mathematics 1985
- Sharon Schwenk, B.A. Mathematics, 1974
- John Stutz, M.S. Physics 1973
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