How many 3 -digit numbers can be formed if the leading digit cannot be zero and repeats are not allowed?
A) 997
B) 504
C) 810
D) 648
E) 900

Question

Quizplus · Accepted Answer

There are 9 choices for the first digit (1 through 9). After the first digit is chosen, there are only 9 choices left for the second digit (since we can't repeat the first digit), and then only 8 choices left for the third digit. Therefore, the total number of 3-digit numbers that can be formed is 9 x 9 x 8 = 648.

How Many 3 -Digit Numbers Can Be Formed If the Leading