How many different 3-digit numbers can be formed using the digits 1, 2, 3, 4, and 5, allowing repetition?Choices:- 60 120 125 135

The solution to this problem involves understanding the fundamental counting principle, which states that if there are m ways to do one thing, and n ways to do another, then there are m*n ways of doing both.

In this case, we are forming a 3-digit number, so there are three "slots" to fill: the hundreds place, the tens place, and the ones place.

1. For the hundreds place, we can choose any of the 5 digits (1, 2, 3, 4, 5). So there are 5 options.

2. For the tens place, we can also choose any of the 5 digits, because repetition is allowed. So there are again 5 options.

3. For the ones place, we again have 5 options, because repetition is allowed.

So, the total number of 3-digit numbers we can form is 5 * 5 * 5 = 125.

Therefore, the correct answer is 125.