Question

The number of different numbers each of six digits that can be formed by using the digits of the numbers 2,2,3,3,9,9 is

• A. 90
• B. 100
• C. 600
• D. 120

Answer 1

The correct option is A 90

This is a type of question in which we have to arrange $n$ things out of which $p,q$ and $r$ are similar or identical things
So in this case $n$ is 6 and $p,q,r$ is $2,2,2$ respectively
Number of 2 is 2
Number of 3 is 2
Number of 9 is 2
$\therefore$ Required number of ways is $\frac{6!}{2!\times 2!\times 2!}=90$