BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Prime # question -GMAT Prep

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 47
Joined: Tue Sep 20, 2011 2:34 pm
Thanked: 1 times
Followed by:1 members

Prime # question -GMAT Prep

by anks17 » Fri Aug 10, 2012 8:44 am
GMAT Experts,

Can you plz confirm the right way to approach the attached question.
Attachments
Number Theory GMAT Prep question.png
Prime # question -GMAT Prep
"doesn't matter ver u r...ur destiny depends upon vho u choose 2 b!!!!"
Top
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 167
Joined: Fri Mar 09, 2012 8:35 pm
Thanked: 39 times
Followed by:3 members

by adthedaddy » Fri Aug 10, 2012 9:58 am
Answer to this is (E).

You may refer following link on MGMAT forum. Its explained nicely.
https://www.manhattangmat.com/forums/for ... t1152.html
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 342
Joined: Wed Jul 08, 2009 8:50 am
Thanked: 214 times
Followed by:19 members
GMAT Score:740

by Birottam Dutta » Fri Aug 10, 2012 10:05 am
Good question!!!

If we break down h(100), we get, h(100) = 2*4*6*......100 = 2^50 (1*2*3*4...*50)

So, h(100) contains all natural numbers upto 50.

Hence, h(100) + 1 cannot have a prime number less than 50 because it will always yield a reminder of 1.

Hence, least prime factor of h(100) + 1 will be greater than 50.

Answer is E!
Top
Post new topic Post Reply
• Page 1 of 1