Question

A building security code has 2 numeric

digits, O through 9, followed by 2 letters.
What is the probability that the first digit
is 9 and the last letter is A?

Answer 1

Explanation:

First number is 1/10

Last letter is 1/26

The second digit is 1/9

The first letter is 1/25

1/10 * 1/26 * 1/9 * 1/25

0.00001709

This assumes no duplication is allowed,

If there are duplications

then 1/10 * 1/10 * 1/26 * 1/26

0.000014782