# Math Help - Another problem....

1. ## Another problem....

If the prime number "a" is larger than 10^5 what is the sum of the multiples of a? This is a math Olympiad question.

2. ## Re: Another problem....

Surely it would be infinity...

3. ## Re: Another problem....

The answers do not include infinty...it's multiple choice.

The answers are one of the following:

a+5
a+2
a+1
10^5-a

I need to know which answer with proof.

4. ## Re: Another problem....

er...it's actually the sum of the common denominators not the multiples..my bad.

5. ## Re: Another problem....

As stated, I would find:

$S=\frac{a}{2}\lim_{n\to\infty}n^2+2=\infty$

6. ## Re: Another problem....

Do you mean the sum of the divisors?

7. ## Re: Another problem....

please clarify your question, sum of divisors of a prime number would be no sense, and the multiples of every number go to infinity.Are you sure that's the question?