MAA MinuteMath: March 13, 2009

Friday, March 13, 2009

March 13, 2009

A traffic light runs repeatedly through the following cycle: green for 30 seconds, then yellow for 3 seconds, and then red for 30 seconds. Leah picks a random three-second time interval to watch the light. What is the probability that the color changes while she is watching?

Interactive version of problem and solution.

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MAA MinuteMath

Exercise your mind daily with a problem from the AMC-8, AMC-10, or AMC-12, provided by Mathematical Association of America's American Mathematics Competitions.

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Curriculum Inspirations is a collection of resources for Middle and High School Math Teachers that demonstrate practical ways to engage students in the lively exploration of mathematics and mathematical thinking using problems from America’s longest-running and most successful mathematics competition. Developed by James Tanton, these resources include Ten Problem Solving Strategy Essays and Curriculum Bursts.

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