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

It is currently 21 Oct 2018, 18:29

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

What is the value of p+q?

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

Hide Tags

Senior PS Moderator
User avatar
V
Joined: 26 Feb 2016
Posts: 3191
Location: India
GPA: 3.12
Premium Member CAT Tests
What is the value of p+q?  [#permalink]

Show Tags

New post 15 Nov 2017, 11:03
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

79% (00:58) correct 21% (00:46) wrong based on 73 sessions

HideShow timer Statistics

What is the value of p+q?

1. r - s = 5
2. rp + rq - sp - sq = 20

Source: Experts Global

_________________

You've got what it takes, but it will take everything you've got

CEO
CEO
User avatar
D
Joined: 12 Sep 2015
Posts: 3024
Location: Canada
Re: What is the value of p+q?  [#permalink]

Show Tags

New post 15 Nov 2017, 11:38
1
Top Contributor
pushpitkc wrote:
What is the value of p+q?

1. r - s = 5
2. rp + rq - sp - sq = 20



Target question: What is the value of p+q?

Statement 1: r - s = 5
No information about p or q
So, statement 1 is NOT SUFFICIENT

Statement 2: rp + rq - sp - sq = 20
We can factor the left side in parts

Factor r from first 2 terms to get: r(p + q) - sp - sq = 20
Factor -s from last 2 terms to get: r(p + q) - s(p + q) = 20
Since we have p + q in common in both parts, we can combine the terms
We get: (r - s)(p + q) = 20
------------------------------------
ASIDE: This last step is no different from simplifying the expression 8k - 3k to get: (8 - 3)k
To be more general: b(something) - c(something) to get: (b - c)(something)
-----------------------------------
Now that we know that (r - s)(p + q) = 20, we can see that p+q can have many different values.
So, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
Statement 1 tells us that r - s = 5
Statement 2 tells us that (r - s)(p + q) = 20
Replace (r - s) with 5 to get: (5)(p + q) = 20
So, IT MUST be the case that (p + q) = 4
Since we can answer the target question with certainty, the combined statements are SUFFICIENT

Answer: C

Cheers,
Brent
_________________

Brent Hanneson – GMATPrepNow.com
Image
Sign up for our free Question of the Day emails

DS Forum Moderator
avatar
P
Joined: 22 Aug 2013
Posts: 1348
Location: India
Premium Member
Re: What is the value of p+q?  [#permalink]

Show Tags

New post 15 Nov 2017, 11:41
(1) r-s=5. Nothing about p and q. Insufficient.

(2) rp+rq-sp-sq = 20. Or r(p+q) - s(p+q) = 20 or
(r-s)(p+q) = 20. Here we have factorised the left hand side. But still we cant say anything about (p+q) unless we know something about (r-s). (Because multiple cases are possible). Insufficient.

Combining the two statements: Substituting r-s=5, we get 5 (p+q) = 20 or p+q = 4. Sufficient.

Hence C answer.
Intern
Intern
User avatar
B
Joined: 10 Nov 2017
Posts: 1
Re: What is the value of p+q?  [#permalink]

Show Tags

New post 15 Nov 2017, 12:00
rp+rq-sp-sq=20
or, r(p+q)-s(p+q)=20
or, (r-s)(p+q)=20
or, 5(p+q)=20
or, (p+q)= 4..ans
Senior PS Moderator
User avatar
V
Joined: 26 Feb 2016
Posts: 3191
Location: India
GPA: 3.12
Premium Member CAT Tests
What is the value of p+q?  [#permalink]

Show Tags

New post 15 Nov 2017, 12:17
hasan4imam wrote:
rp+rq-sp-sq=20
or, r(p+q)-s(p+q)=20
or, (r-s)(p+q)=20
or, 5(p+q)=20
or, (p+q)= 4..ans


Hi hasan4imam

Though you have solved the problem perfectly.
This is a DS question, where the aim is to determine
if the statements are individually/combine to give us
an unique solution

The solution for an DS question is as follows :
A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient to answer the question asked.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient to answer the question asked.
C. BOTH statements (1) and (2) TOGETHER are sufficient to answer the question asked, but NEITHER statement ALONE is sufficient to answer the question asked.
D. EACH statement ALONE is sufficient to answer the question asked.
E. Statements (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data specific to the problem are needed.

So, in this case the answer should be C
(since both the options combined are only enough to answer the question)

Hope that helps you!
_________________

You've got what it takes, but it will take everything you've got

GMAT Club Bot
What is the value of p+q? &nbs [#permalink] 15 Nov 2017, 12:17
Display posts from previous: Sort by

What is the value of p+q?

  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®.