### Number 169 of a continuing series

Martin Gardner died eight years ago, but he left behind a treasure of his writings. Here is from one of his books.

SMITH DROVE at a steady clip along the highway, his wife beside him. “Have you noticed,” he said, “that those annoying signs for Flatz beer seem to be regularly spaced along the road? I wonder how far apart they are.” Mrs. Smith glanced at her wrist watch, then counted the number of Flatz beer signs they passed in one minute. “What an odd coincidence!” exclaimed Smith. “When you multiply that number by ten, it exactly equals the speed of our car in miles per hour.” Assuming that the car’s speed is constant, that the signs are equally spaced and that Mrs. Smith’s minute began and ended with the car midway between two signs, how far is it between one sign and the next?

Gardner, Martin. My Best Mathematical and Logic Puzzles (Dover Recreational Math) (Kindle Locations 347-354). Dover Publications. Kindle Edition.

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