^*HOW TO APPEAR SMARTER THAN YOU ARE*
  This is one of my personal favorites: the "1 in ... trick"...
  if you want to be able to impress anywhere in any group, a
  trick: learn to quickly mentally convert "percentages" to "1
  in..." style. It's easy and probably one of the few really good
  uses of math tricks that I know.

  3%= 1 in 33
  10% = 1 in 10
  20% = 1 in 5

  You restate the percentage in those terms and people ALWAYS go,
  "oooh, he smart!"^