Final answer:
Maria is correct. In mathematics, the factors of a number can be either even or odd, depending on the number itself. Therefore, both Rob and Maria are correct in their statements.
Step-by-step explanation:
Maria is correct.
In mathematics, the factors of a number are the numbers that divide evenly into it. An even number has an even number of factors, while an odd number has an odd number of factors.
Let's take the example of the number 6. The factors of 6 are 1, 2, 3, and 6. This means that 6 has four factors, which is an even number. Therefore, Rob's statement that all numbers have an even number of factors is correct.
However, let's consider the number 9. The factors of 9 are 1, 3, and 9. This means that 9 has three factors, which is an odd number. Therefore, Maria's statement that some numbers have an odd number of factors is also correct.
To summarize, both Rob and Maria are correct. While all numbers have an even number of factors, there are also numbers that have an odd number of factors.