Removed my erroneous post

Cheers,
Brent

g.shankaran wrote:is the integer n odd?

1. n is divisible by 3.
2. 2n divisible by twice as many +ve integers as n.

Statement 1: n is divisible by 3.
If n = 3 --> Odd
If n = 6 --> Even

Not sufficient

Statement 2: 2n divisible by twice as many positive integers as n
Hence, number of factors of 2n is double as of n.

Say, n is even.
Then factors of n are 1, 2,..., a,... and n
Factors of 2n will include all the factors of n and double of them, i.e. factors of 2n are 1, 2,..., a,..., 2a,... and 2n

Note that 2 is common in both of them. Hence number of factors of 2n must be less than twice the number of factors of n. Hence, n is not even. Then n must be odd. (Similarly, we can show that n is in fact odd.)

Sufficient.

The correct answer is B.

Brent@GMATPrepNow wrote:Big point: Notice what happens when we find the number of divisors of 2(400)
Since 800 = (2^5)(5^2), the total number of positive divisors of 800 equals (5+1)(2+1)=30

Hi Brent, the bold part has a calculation error. It would evaluate to (5 + 1)*(2 + 1) = 6*3 = 18

Argh . . . you're totally right Anurag!

And now back to bed

Cheers,
Brent

Wow, I spent a very long time "proving" something that is incorrect.
For my next trick . . .

Cheers,
Brent