GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 20 Oct 2019, 12:07

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

Is x less than 20?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Senior Manager
Senior Manager
avatar
Status: Finally Done. Admitted in Kellogg for 2015 intake
Joined: 25 Jun 2011
Posts: 442
Location: United Kingdom
Concentration: International Business, Strategy
GMAT 1: 730 Q49 V45
GPA: 2.9
WE: Information Technology (Consulting)
Is x less than 20?  [#permalink]

Show Tags

New post 20 Mar 2012, 09:07
6
34
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

80% (00:53) correct 20% (00:57) wrong based on 438 sessions

HideShow timer Statistics

Is x less than 20?

(1) The sum of x and y is less than 20.
(2) y is less than 20.

_________________
Best Regards,
E.

MGMAT 1 --> 530
MGMAT 2--> 640
MGMAT 3 ---> 610
GMAT ==> 730
Most Helpful Expert Reply
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58434
Re: Is x less than 20?  [#permalink]

Show Tags

New post 20 Mar 2012, 09:17
5
5
General Discussion
Manager
Manager
User avatar
Joined: 23 Jun 2008
Posts: 80
Location: Australia
Schools: AGSM '21
GMAT Date: 04-01-2014
Is x less than 20?  [#permalink]

Show Tags

New post 04 Feb 2014, 21:56
1
nfa1rhp wrote:
Is x less than 20?

1) The sum of x and y is less than 20

2) y is less than 20

I thought working together they would be sufficient but they are not.
[/quote]

Ans E

1 & 2 not sufficient : as difference of two numbers does not implicate their magnitude in any way
_________________


Kudos (+1) if you find this post helpful. :)
Intern
Intern
avatar
Joined: 21 Mar 2013
Posts: 10
Re: Is x less than 20?  [#permalink]

Show Tags

New post 01 Mar 2014, 14:16
but if we solve it like this:
subtract
x+y < 20
y < 20

x+y-y<0
x<0

then x will be certainly less than 20...

Why is this approach flawed ?

Bunuel wrote:
enigma123 wrote:
Is x < 20?

1. Sum of x and y is less than 20

2. y is less than 20

How come the answer is E and not A?


Consider two cases:
x=30 and y=-15;
x=15 and y=-15;

Both examples satisfy the statements and give different answers to the question whether x<20. Not sufficient.

Answer: E.
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58434
Re: Is x less than 20?  [#permalink]

Show Tags

New post 02 Mar 2014, 04:20
1
3
mariofelix wrote:
but if we solve it like this:
subtract
x+y < 20
y < 20

x+y-y<0
x<0

then x will be certainly less than 20...

Why is this approach flawed ?

Bunuel wrote:
enigma123 wrote:
Is x < 20?

1. Sum of x and y is less than 20

2. y is less than 20

How come the answer is E and not A?


Consider two cases:
x=30 and y=-15;
x=15 and y=-15;

Both examples satisfy the statements and give different answers to the question whether x<20. Not sufficient.

Answer: E.


That's wrong because you cannot subtract inequalities with signs in the same direction.

ADDING/SUBTRACTING INEQUALITIES:


You can only add inequalities when their signs are in the same direction:

If \(a>b\) and \(c>d\) (signs in same direction: \(>\) and \(>\)) --> \(a+c>b+d\).
Example: \(3<4\) and \(2<5\) --> \(3+2<4+5\).

You can only apply subtraction when their signs are in the opposite directions:

If \(a>b\) and \(c<d\) (signs in opposite direction: \(>\) and \(<\)) --> \(a-c>b-d\) (take the sign of the inequality you subtract from).
Example: \(3<4\) and \(5>1\) --> \(3-5<4-1\).

Adding/subtracting/multiplying/dividing inequalities: help-with-add-subtract-mult-divid-multiple-inequalities-155290.html


Hope it helps.
_________________
Intern
Intern
avatar
Joined: 15 May 2014
Posts: 1
Question about DS - Is x less than 20?  [#permalink]

Show Tags

New post 21 Jul 2014, 16:55
Hi All,

I have a question regarding a data sufficiency problem.

Is x less than 20?

1) x + y < 20
2) y is less than 20


My question refers to 1.). In this case, since it says x + y, can we plug in a negative number in for y even with a + sign in front of it?

ex. if x=25, y=-8,
25 + (-8) = 17
we do not know if x<20, therefore INSUFFICIENT

I am sure this question is pretty basic to most, but it is these small details that seem to throw me off while solving DS problems. Any advice would be very helpful.

BTW - This question is from the CAT on GMATPrep software.

Thanks,
Mike
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58434
Re: Is x less than 20?  [#permalink]

Show Tags

New post 22 Jul 2014, 03:24
MikeA2606 wrote:
Hi All,

I have a question regarding a data sufficiency problem.

Is x less than 20?

1) x + y < 20
2) y is less than 20


My question refers to 1.). In this case, since it says x + y, can we plug in a negative number in for y even with a + sign in front of it?

ex. if x=25, y=-8,
25 + (-8) = 17
we do not know if x<20, therefore INSUFFICIENT

I am sure this question is pretty basic to most, but it is these small details that seem to throw me off while solving DS problems. Any advice would be very helpful.

BTW - This question is from the CAT on GMATPrep software.

Thanks,
Mike


Merging similar topics. Please refer to the discussion above.

As for your question: y is some number, it could be negative, positive or 0. So, you can plug any number you want there.

P.S. Please read carefully and follow: rules-for-posting-please-read-this-before-posting-133935.html Pay attention to rules 3, and 7. Thank you.


_________________
Intern
Intern
avatar
Joined: 17 Oct 2015
Posts: 7
Schools: LBS '18 (S)
Re: Is x less than 20?  [#permalink]

Show Tags

New post 13 Nov 2015, 05:41
For people like me who like equations (especially under time pressure of the GMAT)

For C=>

Just add 1 + 2 (same sign) to get:
x + 2y < 40
x < 40 - 2y

Its then clear x can be any number - depending on y - and less/more than 20... So E.

Further (not needed but why not), the range of x would be:
x > 2y -40
x > 2(20) -40 ( y < 20, so max y ~ 20)
x > 0
Manager
Manager
User avatar
Joined: 18 Jan 2010
Posts: 246
Re: ds inequalities  [#permalink]

Show Tags

New post 27 May 2016, 20:27
1
rahsin wrote:
Is x less than 20 ?

1. The sum of x and y is less than 20.

2. y is less than 20.


Statement 1

x+y<20

say x=5, y=14, sum is 19. so x+y < 20. Also x is less than 20.

Now take x=25, y=-16, sum is 9. so x+y < 20. BUT x is more than 20.

So not sufficient

Statement 2
This statement does not say anything about x. Clearly Not sufficient.

Combining Statements 1 and 2

Our above examples will suit the purpose, as in both cases y is less than 20.

say x=5, y=14, sum is 19. so x+y < 20. Also y is less than 20. Here x is less than 20
Now take x=25, y=-16, sum is 9. so x+y < 20. Also y < 20. BUT x is more than 20.

So even after combining Not sufficient.

(E) is the answer.
Manager
Manager
User avatar
B
Joined: 27 Jan 2013
Posts: 96
Location: India
GMAT 1: 700 Q49 V35
GPA: 3.7
General Math Questions  [#permalink]

Show Tags

New post 13 Jul 2016, 14:04
1
Is x less than 20 ?
(1) The sum of x and y is less than 20.
(2) y is less than 20.



Solution:

Answer should be E. Here it is how:

1: x+y < 20 ---> tells us nothing about y or x. say x=24, y= -10 then x < 20 No. Say x = 17 y =1 then x <20 Yes. --- > Insufficient.
2: y <20 , nothing is told about x. ----> clearly insufficient.

Combined.
x+y < 20 and y <20. Again, use the example given in statement 1. If x=24, y= -10 then x < 20 No. If x = 17, y =1 then x <20 Yes.

Hence answer should be E.

Please give kudos if this helps! :)
SVP
SVP
avatar
B
Joined: 06 Nov 2014
Posts: 1873
Re: Is x less than 20?  [#permalink]

Show Tags

New post 16 Jul 2016, 13:02
rraghun wrote:
Is x less than 20 ?
(1) The sum of x and y is less than 20.
(2) y is less than 20.

My answer is C, The official answer is E.


Required: Is x < 20?
Statement 1: x + y < 20
Case 1: x = 1, y = 18
Case 2: x = 21, y = -29
Nothing can be said about x
INSUFFICIENT

Statement 2: y < 20
This does not give us anything about x
INSUFFICIENT

Combining both statements: x + y < 20 and y < 20
Case 1: x = 21, y = -2
Case 2: x = 18, y = 1
Still nothing can be said about x
INSUFFICIENT

Correct Option: E

Does this help?
Director
Director
User avatar
B
Joined: 04 Jun 2016
Posts: 556
GMAT 1: 750 Q49 V43
Re: Is x less than 20?  [#permalink]

Show Tags

New post 17 Jul 2016, 23:50
enigma123 wrote:
Is x less than 20?

(1) The sum of x and y is less than 20.
(2) y is less than 20.


(1) The sum of x and y is less than 20.
x+y<20 ; infinite possible values of x ; NOT SUFFICIENT

(2) y is less than 20
Doesn't even talk about x; NOT SUFFICIENT

MERGING
x+less than 20<20
Case 1 ) Y is negative
x+(-30)<20 ==> x<50 {{{ Is x less than 20? = NO}}}

Case 1 ) Y is Positive
x+14<20 ==> x<6 {{{Is x less than 20? =YES}}}

NOT SUFFICIENT

ANSWER SHOULD BE E
_________________
Posting an answer without an explanation is "GOD COMPLEX". The world doesn't need any more gods. Please explain you answers properly.
FINAL GOODBYE :- 17th SEPTEMBER 2016. .. 16 March 2017 - I am back but for all purposes please consider me semi-retired.
Director
Director
User avatar
G
Joined: 26 Oct 2016
Posts: 606
Location: United States
Concentration: Marketing, International Business
Schools: HBS '19
GMAT 1: 770 Q51 V44
GPA: 4
WE: Education (Education)
Re: Is x less than 20?  [#permalink]

Show Tags

New post 26 Jan 2017, 06:06
Statement 1: (x + y) < 20
Possible combinations,
1. x = 50, y = -10
2. x = 10, y = 5
so, value of x can be more than 20 or less than 20 we don't know about that.

Not sufficient

Statement 2: No information regarding x.

Not sufficient

1 & 2 Together: Same examples as in statement 1.

Not sufficient

The correct answer is E.
_________________
Thanks & Regards,
Anaira Mitch
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 13316
Re: Is x less than 20?  [#permalink]

Show Tags

New post 28 Jul 2019, 18:13
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.
_________________
GMAT Club Bot
Re: Is x less than 20?   [#permalink] 28 Jul 2019, 18:13
Display posts from previous: Sort by

Is x less than 20?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne