Question

Find the number of arrangements of letters in the word MUMBAI so that the letter B is always next to A

Answer 1

In the word MUMBAI the number of letters is n = 6 of which M repeats twice, i.e., p = 2.

If B is always next to A, i.e., AB, then it forms one unit and remaining 4 letters. Therefore total number of letters n = 5 and p = 2.

∴ number of different ways of arrangements of letters in which B is always next to A

= `("n"!)/("p"!)`

= `(5!)/(2!)`

= `120/2`

= 60.