How many 3-digit numbers can be formed from the digits 1,2,3,4 and 5 assuming that repetition of the digits is not allowed?
A three digit number is to be formed from given 5 digits 1,2,3,4,5.□□□HTO
Now, there are 5 ways to fill ones place.
Since, repetition is not allowed , so tens place can be filled by remaining 4 digits.
So, tens place can be filled in 4 ways.
Similarly, to fill hundreds place, we have 3 digits remaining.
So,hundreds can be filled by 3 ways.
So, required number of ways in which three digit numbers can be formed from the given digits is 5×4×3=60