Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 22 May 2015, 21:56

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Is xy < 6 (1) x < 3 and y < 2 (2) 1/2 < x < 2/3 and y^2 < 64

Author Message
TAGS:
Manager
Joined: 05 Jun 2009
Posts: 112
Followers: 3

Kudos [?]: 62 [1] , given: 4

Is xy < 6 (1) x < 3 and y < 2 (2) 1/2 < x < 2/3 and y^2 < 64 [#permalink]  24 Oct 2009, 04:36
1
KUDOS
1
This post was
BOOKMARKED
00:00

Difficulty:

35% (medium)

Question Stats:

69% (02:09) correct 31% (01:16) wrong based on 140 sessions
Is xy < 6

(1) x < 3 and y < 2

(2) 1/2 < x < 2/3 and y^2 < 64
[Reveal] Spoiler: OA

Last edited by Bunuel on 09 Apr 2012, 11:28, edited 1 time in total.
Edited the question and added the OA
Director
Joined: 01 Apr 2008
Posts: 906
Schools: IIM Lucknow (IPMX) - Class of 2014
Followers: 18

Kudos [?]: 310 [1] , given: 18

Re: Is xy <6 [#permalink]  24 Oct 2009, 04:46
1
KUDOS
IMO B.

stmt1: if both x and y are negative such that the product of their absolute values is > 6 then xy>6. eg. x=-8, y=-3

stmt2: x is +ve, -8<y<8.
Let us take max value of x =2/3 and max value of y=8, the product is <6.
Now, let us take max value of x=2/3 and a negative value of y=-8, the product is -ve and hence < 6.
One more try, take x=2/3 and y=5, the product is <6.
Manager
Joined: 06 Aug 2009
Posts: 76
Followers: 1

Kudos [?]: 5 [0], given: 1

Re: Is xy <6 [#permalink]  24 Oct 2009, 08:37
Economist wrote:
IMO B.

stmt1: if both x and y are negative such that the product of their absolute values is > 6 then xy>6. eg. x=-8, y=-3

stmt2: x is +ve, -8<y<8.
Let us take max value of x =2/3 and max value of y=8, the product is <6.
Now, let us take max value of x=2/3 and a negative value of y=-8, the product is -ve and hence < 6.
One more try, take x=2/3 and y=5, the product is <6.

y^2<64 either becomes
y<+8 or y<-8
OR
mod y < 64, meaning -64<y<64

what am i missing here?
SVP
Joined: 29 Aug 2007
Posts: 2496
Followers: 58

Kudos [?]: 562 [0], given: 19

Re: Is xy <6 [#permalink]  24 Oct 2009, 20:50
tihor wrote:
Economist wrote:
IMO B.

stmt1: if both x and y are negative such that the product of their absolute values is > 6 then xy>6. eg. x=-8, y=-3

stmt2: x is +ve, -8<y<8.
Let us take max value of x =2/3 and max value of y=8, the product is <6.
Now, let us take max value of x=2/3 and a negative value of y=-8, the product is -ve and hence < 6.
One more try, take x=2/3 and y=5, the product is <6.

y^2<64 either becomes
y<+8 or y<-8
OR
mod y < 64, meaning -64<y<64

what am i missing here?

y^2 < 64 mean that -8 < y < 8 because min y^2 is 0 and max is close to 64. In that case, y<8 or y>-8. If y<-8, y could be -10, resulting y^2 = 100, which is >64 and violets the given info in the question.
Whenever you have y^2< 64, y is either +ve or 0, or -ve.

i. y^2 < 64 doesnot mean that -64 < y^2 < 64.
ii. "Mod y < 64, meaning -64<y<64" is not correct.
_________________
Manager
Joined: 15 Apr 2011
Posts: 70
Followers: 0

Kudos [?]: 13 [0], given: 45

Re: Problem : Is xy <6 (1) x < 3 and y < 2 (2) 1/2 < [#permalink]  09 Apr 2012, 11:18
I didn't understand this one. could someone please explain why C is not the answer? thanks.
_________________
Math Expert
Joined: 02 Sep 2009
Posts: 27465
Followers: 4307

Kudos [?]: 42120 [2] , given: 5957

Re: Problem : Is xy <6 (1) x < 3 and y < 2 (2) 1/2 < [#permalink]  09 Apr 2012, 11:31
2
KUDOS
Expert's post
I didn't understand this one. could someone please explain why C is not the answer? thanks.

Is $$xy<6$$?

(1) $$x<3$$ and $$y<2$$ --> now, if both $$x$$ and $$y$$ are equal to zero then $$xy=0<6$$ and the answer will be YES but if both $$x$$ and $$y$$ are small enough negative numbers, for example -10 and -10 then $$xy=100>6$$ and the answer will be NO. Not sufficient.

(2) $$\frac{1}{2}<x<\frac{2}{3}$$ and $$y^2<64$$, which is equivalent to $$-8<y<8$$ --> even if we take the boundary values of $$x$$ and $$y$$ to maixmize their product we'll get: $$xy=\frac{2}{3}*8\approx{5.3}<6$$, so the answer to the question "is $$xy<6$$?" will always be YES. Sufficient.

_________________
Manager
Joined: 15 Apr 2011
Posts: 70
Followers: 0

Kudos [?]: 13 [0], given: 45

Re: Is xy < 6 (1) x < 3 and y < 2 (2) 1/2 < x < 2/3 and y^2 < 64 [#permalink]  09 Apr 2012, 11:41
Bunuel, your explanations are so easy to understand. Thanks!
_________________
Math Expert
Joined: 02 Sep 2009
Posts: 27465
Followers: 4307

Kudos [?]: 42120 [0], given: 5957

Re: Is xy < 6 (1) x < 3 and y < 2 (2) 1/2 < x < 2/3 and y^2 < 64 [#permalink]  28 May 2013, 04:28
Expert's post
Bumping for review and further discussion.
_________________
Manager
Joined: 24 Apr 2013
Posts: 55
Schools: Duke '16
Followers: 0

Kudos [?]: 2 [0], given: 76

Re: Problem : Is xy <6 (1) x < 3 and y < 2 (2) 1/2 < [#permalink]  28 May 2013, 14:14
Bunuel wrote:
I didn't understand this one. could someone please explain why C is not the answer? thanks.

Is $$xy<6$$?

(1) $$x<3$$ and $$y<2$$ --> now, if both $$x$$ and $$y$$ are equal to zero then $$xy=0<6$$ and the answer will be YES but if both $$x$$ and $$y$$ are small enough negative numbers, for example -10 and -10 then $$xy=100>6$$ and the answer will be NO. Not sufficient.

(2) $$\frac{1}{2}<x<\frac{2}{3}$$ and $$y^2<64$$, which is equivalent to $$-8<y<8$$ --> even if we take the boundary values of $$x$$ and $$y$$ to maixmize their product we'll get: $$xy=\frac{2}{3}*8\approx{5.3}<6$$, so the answer to the question "is $$xy<6$$?" will always be YES. Sufficient.

i dont understand i put A....i could answer the question with that information. N why are we letting x times y = to 0 why cant we let it be equal to 1 or 2?

if a number times a number is less than 6......cant we just say use 1?
Math Expert
Joined: 02 Sep 2009
Posts: 27465
Followers: 4307

Kudos [?]: 42120 [1] , given: 5957

Re: Problem : Is xy <6 (1) x < 3 and y < 2 (2) 1/2 < [#permalink]  28 May 2013, 14:23
1
KUDOS
Expert's post
Bunuel wrote:
I didn't understand this one. could someone please explain why C is not the answer? thanks.

Is $$xy<6$$?

(1) $$x<3$$ and $$y<2$$ --> now, if both $$x$$ and $$y$$ are equal to zero then $$xy=0<6$$ and the answer will be YES but if both $$x$$ and $$y$$ are small enough negative numbers, for example -10 and -10 then $$xy=100>6$$ and the answer will be NO. Not sufficient.

(2) $$\frac{1}{2}<x<\frac{2}{3}$$ and $$y^2<64$$, which is equivalent to $$-8<y<8$$ --> even if we take the boundary values of $$x$$ and $$y$$ to maixmize their product we'll get: $$xy=\frac{2}{3}*8\approx{5.3}<6$$, so the answer to the question "is $$xy<6$$?" will always be YES. Sufficient.

i dont understand i put A....i could answer the question with that information. N why are we letting x times y = to 0 why cant we let it be equal to 1 or 2?

if a number times a number is less than 6......cant we just say use 1?

On DS questions when plugging numbers, goal is to prove that the statement is not sufficient. So we should try to get a YES answer with one chosen number(s) and a NO with another.

Now, for x=y=0 we got an YES answer and for x=y=-10 we got a NO answer, thus the statement is NOT sufficient.

Of course we could use some other numbers to get an YES and a NO answers to prove that the statement is not sufficient: x=y=0 and x=y=-10 are just examples of many possible sets.

Hope it's clear.
_________________
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 4921
Followers: 298

Kudos [?]: 54 [0], given: 0

Re: Is xy < 6 (1) x < 3 and y < 2 (2) 1/2 < x < 2/3 and y^2 < 64 [#permalink]  24 Jul 2014, 22:34
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Re: Is xy < 6 (1) x < 3 and y < 2 (2) 1/2 < x < 2/3 and y^2 < 64   [#permalink] 24 Jul 2014, 22:34
Similar topics Replies Last post
Similar
Topics:
2 Is xy < 6 (1) x < 3 and y < 2 (2) 1/2 < x < 2/3 and y^2 < 64 9 06 Nov 2010, 13:00
Is xy<6 (1) x<3 and y<2. (2) 1/2 <x< 2/3 and 2 20 May 2008, 22:35
is xy < 6? i) x<3 and y<2 ii) 1/2 < x < 2/3 2 04 Apr 2008, 09:46
Is xy < 6? (1) x < 3 and y < 2 (2) 1/2 < x < 2/3 and 1 08 Sep 2007, 14:22
Is xy<6? (1) x<3 and y<2 (2) 1/2<x<2/3 and 1 28 Oct 2006, 23:15
Display posts from previous: Sort by