Question

Write the number of arrangements of the letters of the word ′BANANA′ in which two N′s, come together.

Answer 1

Given: The word is BANANA.
It has $6$ letters including three A′s and two N′s.
Considering both N′s together or as a single letter,
We are left with $5$ letters including three A′s.
$\therefore$ Number of arrangements of $5$ things in which $3$ are similar to one kind
$=\frac{5!}{3!}=\frac{5\times 4\times 3!}{3!}=20$
Hence, required number of arrangements of the letters are $20$.