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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?

Illustration of a car parked in an asphalt parking lot.


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

About the University of Idaho

The University of Idaho, home of the Vandals, is Idaho’s land-grant, national research university. From its residential campus in Moscow, U of I serves the state of Idaho through educational centers in Boise, Coeur d’Alene and Idaho Falls, nine research and Extension centers, plus Extension offices in 42 counties. Home to more than 12,000 students statewide, U of I is a leader in student-centered learning and excels at interdisciplinary research, service to businesses and communities, and in advancing diversity, citizenship and global outreach. U of I competes in the Big Sky and Western Athletic conferences. Learn more at uidaho.edu.