Question

Everyone in a group is being assigned a secret code of 3 characters. The first character must be a letter and the second and third are numbers which can not be the same. How many possible codes can be made? O A. 46 O B. 126 C. 2340 O D. 2600

Answer 1

Answer: C. 2340

Explanation:

Hi!

The first character is a letter. There are 26 letters in the alphabet. For each letter you choose a two digit number, but you cannot repeat the digits. There are 100 (0 to 99) two digit numbers, and you have to discard 00, 11, 22, 33, 44, 55, 66, 77, 88, 99. Those are the 10 numbers with repeated digits.

So, for each letter, you have any of 90 possible numbers. The answer is then 26*90 = 2340