You're taking a multiple choice test that has 8 questions. Each of the questions has 5 choices with one correct choice per question. If you select one of these options per question and leave nothing blank in how many ways can you answer the question?

This problem is an example of counting principles, since there are 8 questions and each questions has 5 choices with only one correct answer per question. So the number of ways the exam can be answered is 5 ways per question since there 8 questions

5 x 5 x5 x5 x5 x5 x5 x5 = 390625 ways