Two women apply for a job. They are identical and have the same mother, father and birthday. The interviewer asks, “Are you twins?” to which they honestly reply, “No”.
Three closed boxes have either white marbles, black marbles or both, and they are labeled white, black and both. However, you’re told that each of the labels are wrong. You may reach into one of the boxes and pull out only one marble. Which box should you remove a marble from to determine the contents of all three boxes?
The one labeled both. Since you know it’s labeled incorrectly, it must have all black marbles or all white marbles. After you determine what it contains, you can identify the other two boxes by the process of elimination.
Pencil lead. While modern pencils don’t contain lead, that’s still what we call the graphite compound. When real lead was used in pencils it was mined and nearly everyone has used a pencil at some point in their life.
