A test consists of four multiple-choice questions, each having five possible answers with only one correct option per question. How many different answer combinations will result in the candidate not answering all four questions correctly?

Explanation

There are 4 questions, each with 5 answer choices, so total possible answer patterns are 5^4 = 625. Only one combination corresponds to all answers being correct. Therefore, the number of ways to answer such that not all are correct is 625 - 1 = 624.