Question

How many numbers of $3$ digits can be formed with the digits $1,2,3,4,5$ when digits may be repeated?

Answer 1

The unit’s place can be filled in $5$ ways. Since, the repetition of digits is allowed, therefore ten’s place can be filled in $5$ ways and hundred’s place can also be filled in $5$ ways. Therefore, by the fundamental principle of counting, the required number of three digit numbers $=5\times 5\times 5=125$.