The letter ‘X’. A single x is often used in math as an unknown, along with Mr. X. Two together (XX) make the Roman numeral 20, and three signifies a warning for adult only content, or a warning to other programmers of a problem in source code.
Second. Second place is next to winning. Seconds, the measure of time, pass quickly. Seconding a motion is requested by the chair of the body in Parliament. And the second place finisher in many sporting events such as the Olympics is awarded the silver medal.
And as for why the unit of time is called a second, it goes back to the days of Ptolemy. A second of time is the second small part, or pars minuta secunda, of an hour. (Thanks to Tim J for researching it).
Any 5-letter word with the word ‘one’ somewhere in it. Examples include shone, stone, alone, money, loner, phone or ornery. Note it doesn’t say there is only one letter left, but only ‘one’ left. Tricky tricky.
A sharpshooter hangs up his hat, turns around and walks 5000 meters in one direction, then turns around and shoots his gun, putting a hole right through his hat. How did he do it?
Bill buys three items at the store for exactly $100. The second item costs half as much as the first item, and the third item is half as much as the second.