Question

You have 5 of your favourite books in your school bag. What is the probability that you will pull them out in alphabetical order?

Answer 1

Probability without replacement

$$P(alphabet)={1 \over 5}\cdot {1 \over5-1}\cdot{1 \over 5-2}\cdot{1 \over 5-3}\cdot{1 \over 5-4}={1 \over 5!}={1 \over 120}\approx0.0083$$