Question

What is the number of ways of arrange the letters in the word banana so that no two n's appear togather?

Answer 1

First calculate number of ways of arranging 6 words of banana which is 6!=720

then take two 'n' as single letter and find the number of ways to arrange 5 letters(and two n's) which is = 5! * 2= 120*2 = 240

then,

number of ways to arrange in such a way that no two n occur together is = 720-240= 480