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

It is currently 23 Jan 2019, 03:31

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 January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
  • Key Strategies to Master GMAT SC

     January 26, 2019

     January 26, 2019

     07:00 AM PST

     09:00 AM PST

    Attend this webinar to learn how to leverage Meaning and Logic to solve the most challenging Sentence Correction Questions.
  • Free GMAT Number Properties Webinar

     January 27, 2019

     January 27, 2019

     07:00 AM PST

     09:00 AM PST

    Attend this webinar to learn a structured approach to solve 700+ Number Properties question in less than 2 minutes.

If a, b, c, and d are all positive integers, a = b/5 + 2 and d = c/7 +

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

Hide Tags

 
Intern
Intern
avatar
B
Joined: 04 Dec 2017
Posts: 2
If a, b, c, and d are all positive integers, a = b/5 + 2 and d = c/7 +  [#permalink]

Show Tags

New post Updated on: 23 Jan 2018, 20:02
00:00
A
B
C
D
E

Difficulty:

  55% (hard)

Question Stats:

62% (03:00) correct 38% (02:30) wrong based on 66 sessions

HideShow timer Statistics

If a, b, c, and d are all positive integers, a = b/5 + 2 and d = c/7 + 4, is c*d^(ab) an even number?

(1) 3.5d - 2 is even
(2) b/d is even

Originally posted by BelaHaqi on 23 Jan 2018, 18:35.
Last edited by chetan2u on 23 Jan 2018, 20:02, edited 1 time in total.
corrected the OA
Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 7212
Re: If a, b, c, and d are all positive integers, a = b/5 + 2 and d = c/7 +  [#permalink]

Show Tags

New post 23 Jan 2018, 20:01
2
BelaHaqi wrote:
If a, b, c, and d are all positive integers, a = b/5 + 2 and d = c/7 + 4, is c*d^(ab) an even number?

(1) 3.5d - 2 is even
(2) b/d is even


From the given equations, following comes out..
1) a and b are of same type- both odd or both even
2) similarly c and d - both are odd or both even.
3) if any of c and d is even, our answer is YES
4) b is MULTIPLE of 5 and d is MULTIPLE of 7


Let's see what each statement tells us..
1) 3.5d-2 is even
So d has to be even, otherwise 3.5d-2 will be a decimal.
Ans is YES
Sufficient
2) b/d is even
b is surely even but nothing can be said about d
If b is 70, and d is 7, Ans is ODD
If b is 140 and d is 70, Ans is EVEN..
Insuff

A
_________________

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
B
Joined: 03 Nov 2017
Posts: 12
GMAT 1: 590 Q48 V23
Re: If a, b, c, and d are all positive integers, a = b/5 + 2 and d = c/7 +  [#permalink]

Show Tags

New post 24 Jan 2018, 11:57
In statement 1, it has to be even > 2 right . If d = 2 , we get 5 which is odd.

Sent from my SM-G955U using GMAT Club Forum mobile app
DS Forum Moderator
avatar
P
Joined: 21 Aug 2013
Posts: 1435
Location: India
Premium Member
Re: If a, b, c, and d are all positive integers, a = b/5 + 2 and d = c/7 +  [#permalink]

Show Tags

New post 24 Jan 2018, 22:06
adityanahan wrote:
In statement 1, it has to be even > 2 right . If d = 2 , we get 5 which is odd.

Sent from my SM-G955U using GMAT Club Forum mobile app


Hi Aditya

I think there's no need to write that explicitly in statement 1, because if we take d=2, we get 3.5d - 2 as an odd number, which does NOT satisfy the condition given in statement 1 - that means we have to reject this value of d and take some other value.
If we take d=4 or 8 or 12 etc., then only we get (3.5d - 2) as even, thus from this statement itself, we can conclude that d is a multiple of 4 (and thus even anyway) which will give us c * d^(ab) as even, and thus our question is answered.
Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 7212
Re: If a, b, c, and d are all positive integers, a = b/5 + 2 and d = c/7 +  [#permalink]

Show Tags

New post 24 Jan 2018, 22:08
adityanahan wrote:
In statement 1, it has to be even > 2 right . If d = 2 , we get 5 which is odd.

Sent from my SM-G955U using GMAT Club Forum mobile app



d has to be a MULTIPLE of 4...
Even 6, 10 will give you 3.5d-2 as odd
_________________

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

GMAT Club Bot
Re: If a, b, c, and d are all positive integers, a = b/5 + 2 and d = c/7 + &nbs [#permalink] 24 Jan 2018, 22:08
Display posts from previous: Sort by

If a, b, c, and d are all positive integers, a = b/5 + 2 and d = c/7 +

  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®.