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

It is currently 19 Nov 2018, 21:46

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
Events & Promotions in November
PrevNext
SuMoTuWeThFrSa
28293031123
45678910
11121314151617
18192021222324
2526272829301
Open Detailed Calendar
  • How to QUICKLY Solve GMAT Questions - GMAT Club Chat

     November 20, 2018

     November 20, 2018

     09:00 AM PST

     10:00 AM PST

    The reward for signing up with the registration form and attending the chat is: 6 free examPAL quizzes to practice your new skills after the chat.
  • The winning strategy for 700+ on the GMAT

     November 20, 2018

     November 20, 2018

     06:00 PM EST

     07:00 PM EST

    What people who reach the high 700's do differently? We're going to share insights, tips and strategies from data we collected on over 50,000 students who used examPAL.

M03-35

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

Hide Tags

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50672
M03-35  [#permalink]

Show Tags

New post 15 Sep 2014, 23:21
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

75% (00:28) correct 25% (00:52) wrong based on 198 sessions

HideShow timer Statistics

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50672
Re M03-35  [#permalink]

Show Tags

New post 15 Sep 2014, 23:21
Official Solution:


Statement (1) by itself is sufficient. All the variables equal zero, and the product of the variables is zero; therefore their product is even.

Statement (2) by itself is insufficient. The variables can be either odd or even. If all the variables are even, their product is even; if they are odd, their product is odd.


Answer: A
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

ISB Thread Master
avatar
Joined: 29 Dec 2014
Posts: 74
Concentration: Finance, Strategy
GMAT 1: 640 Q48 V29
GMAT 2: 640 Q43 V34
Re: M03-35  [#permalink]

Show Tags

New post 17 Jun 2015, 20:57
The key here is to realize that zero is even!
MBA Blogger
User avatar
B
Joined: 19 Apr 2014
Posts: 91
Location: India
Concentration: Strategy, Technology
Schools: NTU '19
WE: Analyst (Computer Software)
Re: M03-35  [#permalink]

Show Tags

New post 20 Sep 2015, 03:22
Bunuel wrote:
Official Solution:


Statement (1) by itself is sufficient. All the variables equal zero, and the product of the variables is zero; therefore their product is even.

Statement (2) by itself is insufficient. The variables can be either odd or even. If all the variables are even, their product is even; if they are odd, their product is odd.


Answer: A


Hi Bunuel, Please elaborate on this:
"All the variables equal zero, and the product of the variables is zero;"
_________________

KUDOS please!! If it helped. :)
Warm Regards.
Visit My Blog

Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 7038
Re: M03-35  [#permalink]

Show Tags

New post 20 Sep 2015, 03:40
1
scofield1521 wrote:
Bunuel wrote:
Official Solution:


Statement (1) by itself is sufficient. All the variables equal zero, and the product of the variables is zero; therefore their product is even.

Statement (2) by itself is insufficient. The variables can be either odd or even. If all the variables are even, their product is even; if they are odd, their product is odd.


Answer: A


Hi Bunuel, Please elaborate on this:
"All the variables equal zero, and the product of the variables is zero;"


Hi,
if i may help
all four terms in \(a^2+b^2+c^2+d^2\) are positive as square of any number is always positive, so only possibility for the sum to be zero is when all four terms are 0, otherwise the sum will be some positive integer or positive fraction...
zero is even so suff...
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


GMAT online Tutor

Intern
Intern
avatar
Joined: 03 Nov 2015
Posts: 26
Re: M03-35  [#permalink]

Show Tags

New post 14 Apr 2016, 11:10
We should not consider irrational numbers?
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50672
Re: M03-35  [#permalink]

Show Tags

New post 14 Apr 2016, 11:32
Intern
Intern
avatar
B
Joined: 26 Sep 2016
Posts: 23
Reviews Badge
Re: M03-35  [#permalink]

Show Tags

New post 26 Jun 2017, 06:09
I'm getting lost in all this, can't a and b for example =-1 and c and d equal 1? Wouldn't the sum still be 0? Because 1^2=1 but -1^2=-1. I don't understand when we have to assume that all the numbers must be positive or can be either.
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50672
Re: M03-35  [#permalink]

Show Tags

New post 26 Jun 2017, 07:08
stan3544 wrote:
I'm getting lost in all this, can't a and b for example =-1 and c and d equal 1? Wouldn't the sum still be 0? Because 1^2=1 but -1^2=-1. I don't understand when we have to assume that all the numbers must be positive or can be either.


The square of a number is always more than or equal to 0.

So, if b = -1, then b^2 = (-1)^2 = 1.

Is the product abcd even?

(1) a^2+b^2+c^2+d^2=0 --> number squared is always non-negative (zero or positive), so the sum of 4 non-negative values to be 0 then each must be zero, so abcd=0=even. Sufficient.

(2) a=b=c=d. Clearly insufficient.

Answer: A.

Hope it's clear.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Intern
Intern
avatar
B
Joined: 29 Sep 2017
Posts: 2
CAT Tests
Re: M03-35  [#permalink]

Show Tags

New post 04 Nov 2018, 19:30
Hi Bunuel,

What if both a and b are square root of negative one (-1) and both c and d are square root of positive one (1),
then the answer of first statement will still be zero.
Are we supposed to consider root of negative numbers?
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50672
Re: M03-35  [#permalink]

Show Tags

New post 04 Nov 2018, 20:36
HrusheekeshJoshi wrote:
Hi Bunuel,

What if both a and b are square root of negative one (-1) and both c and d are square root of positive one (1),
then the answer of first statement will still be zero.
Are we supposed to consider root of negative numbers?


Even roots from negative numbers are not defined on the GMAT. All numbers on the GMAT are real numbers.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

GMAT Club Bot
Re: M03-35 &nbs [#permalink] 04 Nov 2018, 20:36
Display posts from previous: Sort by

M03-35

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


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

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

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.