Question

Find the number of four-digit numbers that can be formed using the digits $1,2,5,7,4$ and $6$ if every digit can occur at most once in any number:

• A. $120$
• B. $360$
• C. $720$
• D. $1440$

Answer 1

Answer: (B)

$360$

$1,2,5,7,4,6$ are a total $6$ digits
So, number of four digit numbers that can be formed using these $6$ digits is ${6_P}_4=\frac{6!}{(6-4)!}=\frac{6!}{2!}=6\times 5\times 4\times 3=360$