Question

If no two books are alike, in how many ways can 2 red, 3 green, and
4 blue books be arranged on a shelf so that all the books of the same
colour are together?
(A) 1728 (B) 864 (C) 1800
(D) 1956​

Answer 1

Answer:

⇒ In each arrangement red colour books can be arranged in 2 ways

⇒ green colour books in 3 ways

and blue colour books in 4 ways

Total 3 units are arranged in 3 = 6 ways

∴ Total no. of ways = 3 × 2 × 3 × 4

=6 × 2× 6 × 24

= 1728