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

Redeem

Numbers

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Data Sufficiency |
User avatar
Legendary Member
Posts: 1460
Joined: Tue Dec 29, 2009 1:28 am
Thanked: 135 times
Followed by:7 members

by selango » Mon Jul 12, 2010 9:46 pm
From stmt1,

x is an square of an integer.

X can be 9=3*3,Odd

X can be 4=2*2,Even

Insuff

From stmt2,

x is cube of an integer.

X can be 27=3*3*3,Odd

X can be 64=4*4*4,Even

Insuff

Combining 1 and 2

X is square of integer.X is cube of an integer.

X can be 4,Even

X can be 27,Odd

Still we cant say X is even..Insuff

Hence E

Hope this clarify
--Anand--
Top
Senior | Next Rank: 100 Posts
Posts: 40
Joined: Sat Jan 30, 2010 10:38 am

by vijaynarayanan » Mon Jul 12, 2010 10:00 pm
selango wrote:From stmt1,

x is an square of an integer.

X can be 9=3*3,Odd

X can be 4=2*2,Even

Insuff

From stmt2,

x is cube of an integer.

X can be 27=3*3*3,Odd

X can be 64=4*4*4,Even

Insuff

Combining 1 and 2

X is square of integer.X is cube of an integer.

X can be 4,Even

X can be 27,Odd

Still we cant say X is even..Insuff

Hence E

Hope this clarify
There is only one number - 1 which satisfies both conditions. hence answer should be C. when ur combining shouldn't you combine for same number.
Top
User avatar
Legendary Member
Posts: 1893
Joined: Sun May 30, 2010 11:48 pm
Thanked: 215 times
Followed by:7 members

by kvcpk » Mon Jul 12, 2010 10:01 pm
vijaynarayanan wrote:Image

I feel the answer should be C. Can anyone explain why it is E?
x is square of integer.

let x= 4 = 2^2...Results in YES
let x=9 = 3^2..Results in NO

x is cube of an integer
let x = 8 = 2^3 ...YES
lest x=27 = 3^3...NO

combining:
let x=1 .. 1^3=1^2 = 1..NO
letx=64 .. 8^2=4^3 .. YES

pick E.

@selango -
Be careful when you are combinign both.
X cannot be 4. because, it is not cube of an integer.
Also, X cannot be 27 because, it is not square of an integer.

Hope this helps!!
Top
User avatar
Legendary Member
Posts: 1460
Joined: Tue Dec 29, 2009 1:28 am
Thanked: 135 times
Followed by:7 members

by selango » Mon Jul 12, 2010 10:29 pm
Yes praveen.Somehow missed it.

thanks for correcting my mistake
--Anand--
Top
User avatar
Legendary Member
Posts: 1893
Joined: Sun May 30, 2010 11:48 pm
Thanked: 215 times
Followed by:7 members

by kvcpk » Mon Jul 12, 2010 10:30 pm
selango wrote:Yes praveen.Somehow missed it.

thanks for correcting my mistake
That happens.. No Problem :)
Top
User avatar
Legendary Member
Posts: 1460
Joined: Tue Dec 29, 2009 1:28 am
Thanked: 135 times
Followed by:7 members

by selango » Mon Jul 12, 2010 10:56 pm
We can also have another example.

X can be 729=9^3=81^2,Odd
--Anand--
Top
Legendary Member
Posts: 2326
Joined: Mon Jul 28, 2008 3:54 am
Thanked: 173 times
Followed by:2 members
GMAT Score:710

by gmatmachoman » Mon Jul 12, 2010 11:19 pm
selango wrote:We can also have another example.

X can be 729=9^3=81^2,Odd
shouldn't read like 729=9^3=27^2 ???
Top
User avatar
Legendary Member
Posts: 1460
Joined: Tue Dec 29, 2009 1:28 am
Thanked: 135 times
Followed by:7 members

by selango » Mon Jul 12, 2010 11:49 pm
yes :(
--Anand--
Top
Senior | Next Rank: 100 Posts
Posts: 40
Joined: Sat Jan 30, 2010 10:38 am

by vijaynarayanan » Mon Jul 12, 2010 11:52 pm
Thanks everyone for helping solve this problem
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 » Tue Jul 13, 2010 9:32 am
Another way to look at a x as both a square and a cube of an integer (when combining statements) is to consider x as an integer raised to the sixth power. Any integer raised to the 6th will have both a square root and a cube root.

Knowing that, any integer raised to the 6th means both even and odd integers can be raised which means x can still be even or odd.
Top
Post new topic Post Reply
• Page 1 of 1