Last visit was: 11 Dec 2024, 21:51 It is currently 11 Dec 2024, 21:51
Home
GMAT
Messages
Tests
Schools
Reviews
Social
Chat
My Profile
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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
User avatar
pintukr
User avatar
Joined: 03 Jul 2022
Last visit: 11 Dec 2024
Posts: 1,332
Own Kudos:
922
Given Kudos: 22
GMAT 1: 680 Q49 V34
Products:
My Reviews GMAT Club Tests
GMAT 1: 680 Q49 V34
Posts: 1,332
Kudos: 922
A test was conducted in a school such that students get 1 mark Updated on: 11 Aug 2022, 10:00
Originally posted by pintukr on 11 Aug 2022, 05:44.
Last edited by pintukr on 11 Aug 2022, 10:00, edited 2 times in total.
Kudos
Add Kudos
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

95% (hard)

Question Stats:

47% (03:50) correct 53% (02:29) wrong based on 17 sessions

History

Date
Time
Result
Not Attempted Yet
A test was conducted in a school such that students get 1 mark for a correct answer and loses a third of a mark for a wrong answer. If a student' scored 105 marks and he attempted all the questions, which of the following cannot be the total number of questions in the test?

A. 185
B. 195
C. 205
D. 245
E. 285

(adapted from gmatfree)

Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Problem Solving (PS) Forum
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
ShowHide Answer
Official Answer
B
User avatar
Regor60
User avatar
Joined: 21 Nov 2021
Last visit: 11 Dec 2024
Posts: 484
Own Kudos:
283
 [1]
Given Kudos: 399
Posts: 484
Kudos: 283
 [1]
A test was conducted in a school such that students get 1 mark 11 Aug 2022, 07:06
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I must be missing something.

The total can't be any of the even answers if I understand the question correctly

Posted from my mobile device
User avatar
ThatDudeKnows
User avatar
Joined: 11 May 2022
Last visit: 27 Jun 2024
Posts: 1,078
Own Kudos:
805
Given Kudos: 79
Expert reply
Posts: 1,078
Kudos: 805
A test was conducted in a school such that students get 1 mark 11 Aug 2022, 08:29
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Regor60
I must be missing something.

The total can't be any of the even answers if I understand the question correctly

Posted from my mobile device

It can't be the odd ones, either!! :shock: :shock: :)
User avatar
pintukr
User avatar
Joined: 03 Jul 2022
Last visit: 11 Dec 2024
Posts: 1,332
Own Kudos:
922
Given Kudos: 22
GMAT 1: 680 Q49 V34
Products:
My Reviews GMAT Club Tests
GMAT 1: 680 Q49 V34
Posts: 1,332
Kudos: 922
A test was conducted in a school such that students get 1 mark 11 Aug 2022, 10:11
Kudos
Add Kudos
Bookmarks
Bookmark this Post
A test was conducted in a school such that students get 1 mark for a correct answer and loses a third of a mark for a wrong answer. If a student' scored 105 marks and he attempted all the questions, which of the following cannot be the total number of questions in the test?

A. 185
B. 195
C. 205
D. 245
E. 285

(adapted from gmatfree)

Hi ThatDudeKnows
Regor60

Let Total number of questions = N
Total correct answers = c.............(+1 for every correct answer)
Total wrong answers = N-c.........(-1/3 for every wrong answer)

then, Marks scored = 105 = c*1 - (N-c)/3
105 = c - (N-c)/3
105 = (4c - N)/3
315 = 4c - N
c = (315 + N) / 4

Need to note that c can only be an integer >=0

Putting N = 185, c = (315+185)/4 = 125
Putting N = 195, c = (315+195)/4 = 127.5 (Not Possible, since c is not an integer)
Putting N = 205, c = (315+205)/4 = 130
Putting N = 245, c = (315+245)/4 = 140
Putting N = 285, c = (315+285)/4 = 150

(B) is the correct answer
User avatar
ThatDudeKnows
User avatar
Joined: 11 May 2022
Last visit: 27 Jun 2024
Posts: 1,078
Own Kudos:
805
Given Kudos: 79
Expert reply
Posts: 1,078
Kudos: 805
A test was conducted in a school such that students get 1 mark Updated on: 11 Aug 2022, 10:39
Originally posted by ThatDudeKnows on 11 Aug 2022, 10:21.
Last edited by ThatDudeKnows on 11 Aug 2022, 10:39, edited 3 times in total.
Kudos
Add Kudos
Bookmarks
Bookmark this Post
pintukr
A test was conducted in a school such that students get 1 mark for a correct answer and loses a third of a mark for a wrong answer. If a student' scored 105 marks and he attempted all the questions, which of the following cannot be the total number of questions in the test?

A. 185
B. 195
C. 205
D. 245
E. 285

(adapted from gmatfree)

Hi ThatDudeKnows
Regor60

Let Total number of questions = N
Total correct answers = c.............(+1 for every correct answer)
Total wrong answers = N-c.........(-1/3 for every wrong answer)

then, Marks scored = 105 = c*1 - (N-c)/3
105 = c - (N-c)/3
105 = (4c - N)/3
315 = 4c - N
c = (315 + N) / 4

Need to note that c can only be an integer >=0

Putting N = 185, c = (315+185)/4 = 125
Putting N = 195, c = (315+195)/4 = 127.5 (Not Possible, since c is not an integer)
Putting N = 205, c = (315+205)/4 = 130
Putting N = 245, c = (315+245)/4 = 140
Putting N = 285, c = (315+285)/4 = 150

(B) is the correct answer

You changed the answer choices from those that were originally in your post!! :shock: :think: :x :thumbdown:

In looking at the question and answer choices as they originally appeared prior to the edit, I think the following approach is more efficient.
105 obviously works. If we get one more question correct, we need to get three more questions incorrect.
We therefore have 105+4n where n is any whole number.
Check the answer choices.
185 works.
195 doesn't.

Answer choice B.

Note that 4n must be even, so 105+4n must be even. This is how Regor60 very quickly knew that the even answer choices that were in the original post wouldn't work.
User avatar
pintukr
User avatar
Joined: 03 Jul 2022
Last visit: 11 Dec 2024
Posts: 1,332
Own Kudos:
922
Given Kudos: 22
GMAT 1: 680 Q49 V34
Products:
My Reviews GMAT Club Tests
GMAT 1: 680 Q49 V34
Posts: 1,332
Kudos: 922
A test was conducted in a school such that students get 1 mark 11 Aug 2022, 10:34
Kudos
Add Kudos
Bookmarks
Bookmark this Post
ThatDudeKnows

Thanks for raising the query in your original post.

Have now amended the answer choices appropriately, as desired.

Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Problem Solving (PS) Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
Moderators:
Bunuel
Math Expert
97815 posts
yashikaaggarwal
Senior Moderator - Masters Forum
3116 posts