Question

A locker combination has three nonzero digits, and the digits cannot be repeated. The first two digits are 1 and 2. What is the probability that the third digit is 3?

Answer 1

Approximately 14% or 1/7

Explanation:

To solve this problem, first find the ratio of 3 to the possible numbers.

There are 9 possible digits in one space on a non-zero combination lock. However, digits cannot be repeated, and 1 and 2 are already taken. Therefore, there are 7 possible digits (9 - 2 = 7). Therefore, the ratio of getting a 3 to possible digits is 1:7, as there is 1 '3' and 7 others.

As a fraction, 1:7 is 1/7. As a percentage, 1/7 is about 14%. Therefore, there is approximately a 14% chance that the third digit will be 3.