MediumMath and Logic
Ways to arrange 8 books on a shelf?
Riddle
Ways to arrange 8 books on a shelf?
Choose an answer
A.64
B.5,000
C.100,000
D.40320
Hint: It's a word with 0 letters, starting with "4".
Answer
40320
Why this is the answer
The number of permutations is n factorial (n!). For 8 books, it is 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1 = 40,320.
This riddle is filed under Math Riddles and rated Medium.