The number of ways in which four S come consecutively in the word MSSISSIPPI, is

Options

A. 420
B. 840
C. 210
D. 630

Answer

D

Explanation

There are 11 letters viz. 4S's 4I's, 2P's and M in the word MISSISSIPPI. Considering 4S's as one letter, we have 8 letters which can be arranged in `(8!)/(4!2!)` ways. But, 4S's can be put
together in `(4!)/(4!)=1` way.
`:.` Total number of words `=(8!)/(4!2!)xx(4!)/(4!)=(8!)/(4!2!)=840`.