A man wants to cross a home, which has 2 doors on one side and 1 door on other site. He has 2 x 1=2 ways for it.
Choose the correct choice from the following options.
A) 1	B) 2	C) 3	D) 4	E) 5
The product of first ‘n’ natural numbers is denoted by n!.   n! = n(n-1) (n-2) ………………..3.2.1.   Ex. 5! = 5 x 4 x 3 x 2 x 1 =120   Note 0! = 1   Proof n! =n, (n-1)!   Or (n-1)! = [n x (n-1)!]/n = n! /n   Putting n = 1, we have   O! = 1!/1   or 0 = 1   1
<result>A</result>
A man wants to cross a home, which has 2 doors on one side and 1 door on other site. He has 2 x 1=2 ways for it.