GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

 It is currently 24 Jan 2020, 01:25

### 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

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

# Each student at a certain Mathematics exam either solved the hardest

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 60630
Each student at a certain Mathematics exam either solved the hardest  [#permalink]

### Show Tags

07 Nov 2019, 02:53
00:00

Difficulty:

55% (hard)

Question Stats:

47% (02:56) correct 53% (01:51) wrong based on 14 sessions

### HideShow timer Statistics

Each student at a certain Mathematics exam either solved the hardest problem correctly or incorrectly. What percent of the examinees solved the hardest problem correctly?

(1) The average score of those students who solved the hardest problem correctly was 12 more than the average score of all students.
(2) The average score of those students who solved the hardest problem incorrectly was 3 less than the average score of all students.

Are You Up For the Challenge: 700 Level Questions

_________________
Math Expert
Joined: 02 Aug 2009
Posts: 8336
Re: Each student at a certain Mathematics exam either solved the hardest  [#permalink]

### Show Tags

07 Nov 2019, 21:20
Bunuel wrote:
Each student at a certain Mathematics exam either solved the hardest problem correctly or incorrectly. What percent of the examinees solved the hardest problem correctly?

(1) The average score of those students who solved the hardest problem correctly was 12 more than the average score of all students.
(2) The average score of those students who solved the hardest problem incorrectly was 3 less than the average score of all students.

Are You Up For the Challenge: 700 Level Questions

Note :- I would take that the marks are 1 for correct and 0 for wrong and no negative marking..

Statements individually are not sufficient as they talk of a particular group to overall only..

So the combined will give us the answer..

C

To solve it, use weighted average method..

...Correct ....total......incorrect
..x+12.........x............x-3

Fraction of students answered correctly = $$\frac{x-(x-3)}{x+12-(x-3)}=\frac{3}{15}=\frac{1}{5}$$=20%
_________________
Re: Each student at a certain Mathematics exam either solved the hardest   [#permalink] 07 Nov 2019, 21:20
Display posts from previous: Sort by