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For any positive integer n, π(n) represents the number of fa

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For any positive integer n, π(n) represents the number of fa [#permalink] New post   04 Apr 2018, 12:33
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For any positive integer n, \(\pi(n)\) represents the number of factors of n, inclusive of 1 and itself. a and b are prime numbers

Quantity A
Quantity B
\(\pi(a) + \pi(b)\)
\(\pi(a * b)\)


A. The quantity in Column A is greater
B. The quantity in Column B is greater
C. The two quantities are equal
D. The relationship cannot be determined from the information given
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C
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Re: For any positive integer n, π(n) represents the number of fa [#permalink] New post   04 Apr 2018, 15:43
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Answer: C (DOUBTS)
A: P(a) + P(b)
The only factors of a prime number are 1 and the number itself.
So P(a) + P(b) always equals 2+2 = 4

B: P(a*b)
The factors of a*b are 1, a, b, a*b. Why not more than 4? Because no new divider is produced with multiplying a to b. If there were any it was a factor of a or b (a factor other than a and b themselves and a) and thus a or b couldn’t be prime. So factors of a*b are 4 numbers.
For example if a = 3 and b = 11 then P(a*b) = P(33) = 4 (1, 3, 11, 33)

A and B are both 4 and equal. The answer is C.
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Re: For any positive integer n, π(n) represents the number of fa [#permalink] New post   06 May 2018, 18:29
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I have reservation on the ans
because it could be a case of \(a = b\)
and hence qty B can have 3 factors
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Re: For any positive integer n, π(n) represents the number of fa [#permalink] New post   06 May 2018, 18:39
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amorphous wrote:
I have reservation on the ans
because it could be a case of \(a = b\)
and hence qty B can have 3 factors


I second that thought if a = b then \(\pi(a*b)\) will have 3 factors 1, a , b and a*b.
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Re: For any positive integer n, π(n) represents the number of fa [#permalink] New post   27 Feb 2019, 10:47
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Hi if a=b at this style the quantity of B has just 3 factor, am i right? for example put a and b equal to 2 now we see that it has just 3 factor
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Re: For any positive integer n, π(n) represents the number of fa [#permalink] New post   09 Mar 2019, 11:41
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shahab1987 wrote:
Hi if a=b at this style the quantity of B has just 3 factor, am i right? for example put a and b equal to 2 now we see that it has just 3 factor


Yes, it seems that if a = b, then quantity B could be 3. This isn't an official question, so it should say "a and b are different prime numbers," or have D as the answer.
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Re: For any positive integer n, π(n) represents the number of fa [#permalink] New post   05 Jun 2021, 11:02
Hello from the GRE Prep Club BumpBot!

Thanks to another GRE Prep Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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Re: For any positive integer n, π(n) represents the number of fa [#permalink]
05 Jun 2021, 11:02
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