Between 20 and 28 students signed up for the chess club. The students could not be divided exactly into groups of 2, 3, 4 and 5. How many students signed up for the chess club? Show your work

Answer 1

You can eliminate the even numbers because they're divisible by 2. You can eliminate 25 because it's divisible by 5. Then eliminate 21 and 27, both divisible by 3. What is your answer?