Casey has forgotten the combination to a lock. The lock has three dials with the numbers 1 , 2 , and 3 . What is the probability that the combination starts with 2 ? CLEAR CHECK How many different numbers can be made using the dials? What is the probability that the combination starts with 2 ?
There are 3 possible numbers for each dial (1, 2, 3), so the total number of different combinations that can be made with the three dials is 3 x 3 x 3 = 27.
Since Casey wants the combination to start with 2, there are still 3 possible numbers for the second and third dials (2, 1, 3).
Therefore, the probability that the combination starts with 2 is 1/3, because there is only 1 out of 3 possible numbers (2) that can be used as the first digit.