Question: In many countries the license plates consist of a string of seven characters such that the first three are letters and the last four are numbers. If each such string of seven characters is equally likely, what is the probability that the string of three letters begins with a W and the string of four numbers begins with a 4?

(Hint. Assume an alphabet of 26 letters. The number of possible such license plates is found in Example).

Example: a. For each of the following tasks specify the stages, the number of outcomes of each stage and the number of outcomes of the task.

b. Form a string of seven characters such that the first three are letters and the last four are numbers.