Between two book-ends in your study are displayed your four favourite love story books. If you decide to arrange the four books in every possible combination and moved just one book every minute, how long would it take you ?
Correct Answer: 48 minutes
Explanation:
Possible arrangements for 4 books are 4x3x2x1 = 24
For making a new arrangement, two books are required to be moved.
One book takes one minute, then for 2 books
So total 24 x 2 = 48 mins.
