Suppose that to land on Free Parking in the game of Monopoly, you will need to roll a 3, and to land on Chance you will need to roll a 7. What is the probability that on your roll of two fair, six-sided dice that you will land on either Free Parking or Chance?
3 = 1,2 or 2,1 = 2/36
7 = 6,1 or 1,6 or 5,2 or 2,5 or 3,4 or 4,3 = ?
Either-or probabilities are found by adding the individual probabilities.