For a college application, Macawi must select one of five topics on which to write a short essay. She must also select a different topic from the list for a longer essay. How many ways can she choose the topics for the two essays?

Answer 1

For the first essay, she has 5 choices. For the second, she cannot repeat the same topic, so she is left with 5-1=4 choices.
By the multiplication principle, she has ? choices?

Answer 2

20

Answer 3

Correct!