How many license plates are possible using three letters followed by three digits if no letter can be repeated?

Idon’t understand this.. will someone ? will mark brainliest along with 20 points.

Answer this question, only if you know the answer. 30 points and brainliest!

Arestaurant offers a $12 dinner special that has 5 choices for an appetizer, 12 choices for an entrée, and 4 choices for a dessert. how many different meals are available when you select an appetizer, an entrée, and a dessert? a meal can be chosen in nothing ways. (type a whole number.)