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

Redeem

Maximum value of an expression

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
Senior | Next Rank: 100 Posts
Posts: 75
Joined: Thu Oct 23, 2008 4:25 am
Thanked: 6 times
GMAT Score:620

by madhukumar_v » Wed Aug 04, 2010 7:01 pm
IMO 6912.

X can be -ve, since it has a square.

so lets say X and Y are equal, and Y=12;

So, Y^3= 1728

Look at answers which one is divisible by 1728, its 6912. hence B.
Top
Senior | Next Rank: 100 Posts
Posts: 81
Joined: Wed Jul 07, 2010 2:21 pm
Thanked: 12 times
Followed by:2 members
GMAT Score:760

by barcebal » Wed Aug 04, 2010 9:58 pm
this question is missing something...

Because you could have x=-100,000 y=100,000 and z=12 which is way bigger than any choice there.

Need more info (are they all positive; are they all distinct; are they all integers?)
Top
Master | Next Rank: 500 Posts
Posts: 231
Joined: Thu Apr 12, 2007 2:45 am
Thanked: 5 times
Followed by:1 members

by winnerhere » Fri Aug 06, 2010 8:43 am
hi people,

x,y,z > 0
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 362
Joined: Fri Oct 02, 2009 4:18 am
Thanked: 26 times
Followed by:1 members

by indiantiger » Fri Aug 06, 2010 10:34 am
Where is the choice E?
"Single Malt is better than Blended"
Top
User avatar
Senior | Next Rank: 100 Posts
Posts: 55
Joined: Mon Sep 07, 2009 9:11 pm
Location: California
Thanked: 4 times

by nithi_mystics » Fri Aug 06, 2010 12:34 pm
Is the answer B?
Thanks
Nithi
Top
Master | Next Rank: 500 Posts
Posts: 231
Joined: Thu Apr 12, 2007 2:45 am
Thanked: 5 times
Followed by:1 members

by winnerhere » Sat Aug 07, 2010 11:07 pm
nithi_mystics wrote:Is the answer B?
yes..could you please explain how u got this answer?
Top
User avatar
Senior | Next Rank: 100 Posts
Posts: 55
Joined: Mon Sep 07, 2009 9:11 pm
Location: California
Thanked: 4 times

by nithi_mystics » Sun Aug 08, 2010 4:19 am
It was trial and error method.

Since we want the max value, I did not chose 1 for x,y or z. Similarly no 0.
So we are left with the numbers, 2,3,4,5,6,7,8

If we take 3 numbers that add up to 12 (say 4,6,2), we would assign the highest value to y(since the term has y^3), the second highest value to x (since it has a square) and the least value to z.

So I tried the following,

x y z x+y+z (x^2)(y^3)(z)
2 8 2 12 4096
4 6 2 12 6912
3 7 2 12 6174
5 5 2 12 6250

Hope this helps! But I am sure that should be some other easy way of doing it.
winnerhere wrote:
nithi_mystics wrote:Is the answer B?
yes..could you please explain how u got this answer?
Thanks
Nithi
Top
Post new topic Post Reply
• Page 1 of 1