It is currently 17 Nov 2017, 22:16

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

Events & Promotions in June
Open Detailed Calendar

A student responded to all of the 22 questions on a test and

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

Hide Tags

Manager
Manager
avatar
Joined: 05 Sep 2007
Posts: 144

Kudos [?]: 52 [0], given: 0

Location: New York
A student responded to all of the 22 questions on a test and [#permalink]

Show Tags

New post 27 Mar 2008, 19:17
10
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

70% (01:38) correct 30% (01:48) wrong based on 775 sessions

HideShow timer Statistics

A student responded to all of the 22 questions on a test and received a score of 63.5. If the scores were derived by adding 3.5 points for each correct answer and deducting 1 point for each incorrect answer, how many questions did the student answer incorrectly?

A. 3
B. 4
C. 15
D. 18
E. 20
[Reveal] Spoiler: OA

Last edited by Bunuel on 01 Jul 2012, 02:39, edited 1 time in total.
Added the OA.

Kudos [?]: 52 [0], given: 0

4 KUDOS received
Senior Manager
Senior Manager
avatar
Joined: 15 Aug 2007
Posts: 252

Kudos [?]: 72 [4], given: 0

Schools: Chicago Booth
Re: PS: test [#permalink]

Show Tags

New post 27 Mar 2008, 19:27
4
This post received
KUDOS
A-3

If x is the number of questions answered correctly...
3.5x - (22-x)*1 = 63.5
x = 19
So number of wrong answers=22-19=3

Kudos [?]: 72 [4], given: 0

Manager
Manager
avatar
Joined: 05 Sep 2007
Posts: 144

Kudos [?]: 52 [0], given: 0

Location: New York
Re: PS: test [#permalink]

Show Tags

New post 27 Mar 2008, 19:38
sreehari wrote:
A-3

If x is the number of questions answered correctly...
3.5x - (22-x)*1 = 63.5
x = 19
So number of wrong answers=22-19=3


how did you come up with 3.5x - (22-x)*1 if it says that "by adding 3.5 points for each correct answer and deducting 1 point for each incorrect answer"???

Kudos [?]: 52 [0], given: 0

1 KUDOS received
Manager
Manager
User avatar
Joined: 14 Sep 2007
Posts: 98

Kudos [?]: 22 [1], given: 0

Re: PS: test [#permalink]

Show Tags

New post 28 Mar 2008, 07:43
1
This post received
KUDOS
el1981 wrote:
A student responded to all of the 22 questions on a test and received a score of 63.5. If the scores were derived by adding 3.5 points for each correct answer and deducting 1 point for each incorrect answer, how many questions did the student answer incorrectly?
(A) 3
(B) 4
(C) 15
(D) 18
(E) 20


Let the number of correct answers be X
The number of incorrect answers will be 22-X
For each correct answer the student got 3.5 points for a total of 3.5X
For each incorrect answer one point was taken out which is equivalent to -(22-X)
The total he got for that was 63.5

So in short you have the following equation and solution.

3.5X-(22-X) = 63.5
3.5X-22+X = 63.5
4.5X = 63.5+22
4.5X = 85.5
4.5X/4.5 = 85.5/4.5
X = 19
So incorrect answers will be 22-X = 22-19 = 3.

Kudos [?]: 22 [1], given: 0

10 KUDOS received
Director
Director
avatar
Joined: 18 Jul 2006
Posts: 523

Kudos [?]: 71 [10], given: 0

Re: PS: test [#permalink]

Show Tags

New post 31 Mar 2008, 01:20
10
This post received
KUDOS
1
This post was
BOOKMARKED
el1981 wrote:
A student responded to all of the 22 questions on a test and received a score of 63.5. If the scores were derived by adding 3.5 points for each correct answer and deducting 1 point for each incorrect answer, how many questions did the student answer incorrectly?
(A) 3
(B) 4
(C) 15
(D) 18
(E) 20

This question can be answered without solving.
Total has 0.5 at the end, so no of correct answers should be odd, in turn no of incorrect answers must be odd too. A & C are only possible answers. C would drop the score too low so answer must be A.

Kudos [?]: 71 [10], given: 0

Intern
Intern
avatar
Joined: 30 Jun 2012
Posts: 3

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

Re: A student responded to all of the 22 questions on a test and [#permalink]

Show Tags

New post 30 Jun 2012, 12:17
Hi,

what does ,,total has O,5´´ mean?

Thanks in advance

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

Expert Post
5 KUDOS received
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42248

Kudos [?]: 132526 [5], given: 12324

Re: A student responded to all of the 22 questions on a test and [#permalink]

Show Tags

New post 01 Jul 2012, 03:31
5
This post received
KUDOS
Expert's post
2
This post was
BOOKMARKED
yuyalm wrote:
Hi,

what does ,,total has O,5´´ mean?

Thanks in advance


Juaz uses the following approach:

A student responded to all of the 22 questions on a test and received a score of 63.5. If the scores were derived by adding 3.5 points for each correct answer and deducting 1 point for each incorrect answer, how many questions did the student answer incorrectly?
(A) 3
(B) 4
(C) 15
(D) 18
(E) 20

We have that 3.5*x-1*y=63.5, where x and y are the # of correct and incorrect answers.

Notice that x must be odd number in order the sum (63.5) to have 5 as the tenths digit (if x=even then 3.5*x-1*y=integer). So, y=22-x=22-odd=odd. There are only two odd choices 3 and 15. y cannot be 15 since in this case the total score would be less than 63.5, so y=3.

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

Kudos [?]: 132526 [5], given: 12324

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 15710

Kudos [?]: 281 [0], given: 0

Premium Member
Re: A student responded to all of the 22 questions on a test and [#permalink]

Show Tags

New post 20 Sep 2013, 05:09
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 Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Kudos [?]: 281 [0], given: 0

Manager
Manager
User avatar
Status: folding sleeves up
Joined: 26 Apr 2013
Posts: 155

Kudos [?]: 139 [0], given: 39

Location: India
Concentration: Finance, Strategy
GMAT 1: 530 Q39 V23
GMAT 2: 560 Q42 V26
GPA: 3.5
WE: Consulting (Computer Hardware)
Re: A student responded to all of the 22 questions on a test and [#permalink]

Show Tags

New post 26 Sep 2013, 11:44
el1981 wrote:
A student responded to all of the 22 questions on a test and received a score of 63.5. If the scores were derived by adding 3.5 points for each correct answer and deducting 1 point for each incorrect answer, how many questions did the student answer incorrectly?

A. 3
B. 4
C. 15
D. 18
E. 20



sol:

x+y=22
3.5X - y = 63.5

X=19 and y =3

But Bunuel's method is super crazy and fastest

Kudos [?]: 139 [0], given: 39

Intern
Intern
avatar
Joined: 14 Mar 2013
Posts: 48

Kudos [?]: 67 [0], given: 119

Location: United States
Concentration: General Management, Leadership
GMAT Date: 12-03-2013
WE: General Management (Retail)
Re: PS: test [#permalink]

Show Tags

New post 20 Nov 2013, 03:11
el1981 wrote:
sreehari wrote:
A-3

If x is the number of questions answered correctly...
3.5x - (22-x)*1 = 63.5
x = 19
So number of wrong answers=22-19=3


how did you come up with 3.5x - (22-x)*1 if it says that "by adding 3.5 points for each correct answer and deducting 1 point for each incorrect answer"???



When I was trying this question I didn't figured out this shortcut, so I took the long road:

Step 1. Tried 15 erros first + 7 correct → 7*3.5 < 63.5 » conclusion: must be more correct questions than 7.
Step 2. Tried 4 erros first + 18 correct → 18*3.5 < 63.5 » conclusion: must be more correct questions than 18.
The only answer is A.

Kudos [?]: 67 [0], given: 119

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 15710

Kudos [?]: 281 [0], given: 0

Premium Member
Re: A student responded to all of the 22 questions on a test and [#permalink]

Show Tags

New post 07 Dec 2014, 13:58
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 Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Kudos [?]: 281 [0], given: 0

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 15710

Kudos [?]: 281 [0], given: 0

Premium Member
Re: A student responded to all of the 22 questions on a test and [#permalink]

Show Tags

New post 03 Feb 2016, 06:31
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 Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Kudos [?]: 281 [0], given: 0

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 15710

Kudos [?]: 281 [0], given: 0

Premium Member
Re: A student responded to all of the 22 questions on a test and [#permalink]

Show Tags

New post 31 Mar 2017, 10:42
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 Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Kudos [?]: 281 [0], given: 0

Senior Manager
Senior Manager
avatar
B
Joined: 06 Dec 2016
Posts: 256

Kudos [?]: 25 [0], given: 10

Re: A student responded to all of the 22 questions on a test and [#permalink]

Show Tags

New post 31 Mar 2017, 13:29
An easier way to do this is process elimination. Let's start with answer A
If he answered 3 wrong then he got 19 correct
19 x 3.5 = 66.3 - 3 = 63.5

No need to work out the other four answers

Answer is A

Kudos [?]: 25 [0], given: 10

Re: A student responded to all of the 22 questions on a test and   [#permalink] 31 Mar 2017, 13:29
Display posts from previous: Sort by

A student responded to all of the 22 questions on a test and

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


GMAT Club MBA Forum Home| About| Terms and Conditions| 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®.