Answer:
1680 ways
Step-by-step explanation:
From the question,
nPr = n!/(n-r)!.................. Equation 1
Where, n = Total number of books to chose from, r = number of books to be arranged in the shelf.
Given: n = 8 books, r = 4 books.
Substitute into equation 1
8P4 = 8!/(8-4)!
8P4 = 8!/4!
8P4 = (8×7×6×5×4!)/4!
8P4 = 1680 ways.
Hence the number of ways 4 books can be arranged in a shelf if there are 8 books to chose from is 1680 ways
