By joseph degrazia

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The giant golden book of mathematics : exploring the world of numbers and space

A proof of the technology of numbers and house, with uncomplicated demonstrations of mathematics, algebra, trigonometry, arithmetic in song and paintings, and together with a few methods and video games utilizing numbers.

Extra info for Math is Fun

Example text

100. Short circuit. When a short circuit occurred, Ethel searched her drawer for candles and found two of equal length. One was a little thicker than the other, and would burn five hours, the thinner one would burn only four. However, the electrical trouble did not last as long as the life expectancy of the candles. When it was all over, Ethel found that the stump of one of the candles was four times as long as that of the other. Since Ethel was mathematically minded she had no trouble figuring out 63 how long it had been until the blown-out fuse was replaced.

Foreman and manager. The foreman in a little factory is 48. How old is the plant manager if the foreman is now twice as old as the manager was when the foreman was as old as the manager is now? 57. Four generations. There is an old Civil War veteran who has a son, a grandson, and a great-grandson. He and his great-grandson together are as old as his son and grandson together. If you turn his age around (that is, take the units for tens and vice versa) you will get the age of his son, and if you turn around the age of his grandson, you will get the age of his great-grandson.

Imagine a railroad station clock with the second-hand on the same axis as the two other hands. How often in a 24-hour day, will the second-hand be parallel to either of the two other hands? 74. The equilateral triangle. Let us imagine that all three hands of a clock are of the same length. Now, is it possible that at any time the points of the hands form an equilateral triangle? In case this should prove impossible, at what moment will the three hands come closest to the desired position? 75. Three clocks.