Problem Solving

I'm posting tough math problems that I've received from Kirtanasarin on Test Magic
https://www.urch.com/forums/just-finishe ... notes.html

I've basically reclassified and split them up to 2 different word doc. Also added a few of my own problems.

Note there are two documents here:
1. gmat more difficult questions
2. permutations & combinations

Do you have answer with explanation?

ssang, thank you for sharing this. But are you sure there is no copyright issues with these questions.

richardwang6430 wrote:Do you have answer with explanation?

Hey richard, just post the questions you have trouble with on the forum. I am sure you will get the required explanations and answers

1. 2n is an integer
2. 3n is an integer

Data sufficiency qstn in the attached document. Answer given is D. Can some one explain how?

This is my answer.

1. Insufficient.

if n = 1/2 2n is integer. but n is not integer
if n= 2 , 2n is integer and n is integer.

2. Insufficient

if n = 1/3 3n is integer. but n is not integer
if n= 3 , 3n is integer and n is integer.

Both together if 2n is integer and 3n is integer,
then n is inetger . Sufficient.
IMO C[/spoiler]