What's New -  April, 2015

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April 13, 2015:  Here's an interesting little puzzle that requires some human thought to solve efficiently:

A farmer tells his son to select five watermelons to take to market. Because the watermelons are sold by weight, they must be put on a scale before the trip to town, but the son makes a small mistake and weighs them in pairs. Here are the weights he comes up with, in pounds: 20, 22, ,23, 24, 25, 26, 27, 28, 30, 31.  How much does each of the watermelons weigh?  (Source: Sit & Solve® Brainteasers (Sit & Solve® Series)

The Weighing Watermelons program posted today implements the solving strategy.

April 19, 2015:

A buddy of mine is designing a Veteran's Day monument which will consist of panels representing the Armed Forces services and aligned in such a way that the sun will cast a shadow on the memorial plaque on November 11 at 11:AM.  At his location, he thought that the sun would cast the shadow again in February when the the sun will be at the same altitude at that hour.  I took advantage of the opportunity to educate him about the  "analemma" figure 8 shape of the sun's path through the sky and assure him that the February sun at 11 AM will be about 10 degrees further East than the November path.  I updated  AstroDemo Version 2.0, our Astronomy unit test program, with an "animated" analemma. That option  helped me determine that at 11:11 AM in Lucedale, MS, the crossing point of the figure 8 occurs on February 12 as days are getting longer and August 29 on the way back down, so no problem for Jim's project!

 Yes J!
 No L

April 29, 2015:  Three points are placed randomly on the circumference of a circle. What is the probability that all three points lie within same semicircle?   Check out Circular Reasoning to verify your answer.