The magic word – please. It makes people do things they otherwise wouldn’t be inclined to do. When parents are teaching children about manners, they call it the magic word and wait to fulfill a request until the child says please. Once the child says it, the parent feels bound to do it to show the child that it works.
A clock. It runs all the time, it “sings” for hourly chimes, cuckoos or alarms, it doesn’t have a head (but does have hands) and you look a clock in the face to tell the time.
Farmer Finnegan needs to build a fence to keep his horses on his property. He only has a little over 1.5 miles of fence materials, but there’s also a mile-long straight river running through his property. What shape should he use for the fenced in area to give his horses the most space possible?
Our dear friend Finnegan should build a half-circle fence with the river as the diameter, giving the horses about 0.4 square miles to frolic and play in.
Area of semi-circle = πr2 / 2 = π × .5 miles2 / 2 = 0.3927
A variation of this brain teaser includes laser printers (they were invented by Gary Starkweather) and bulletproof vests (invented by Casimir Zeglen using silk, though modern vests use Kevlar, so it’s halfway right).
Mr. and Mrs. Webster were on a holiday shopping excursion. On their way to the car after leaving the store, Mr. Webster complained he was tired from carrying so many packages. Mrs. Webster, the kindly thing that she was, replied, “Quit your complaining Walter! If you gave me just one of your packages, I’d have twice as many as you. And if I gave you one of mine, we’d have the same.”
How many packages were Mr. and Mrs. Webster each carrying?