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

It is currently 25 Jan 2020, 14:00

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

Rabia must earn an average (arithmetic mean) score of S percent to

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

Hide Tags

Find Similar Topics 
Intern
Intern
avatar
B
Joined: 22 Feb 2016
Posts: 13
Rabia must earn an average (arithmetic mean) score of S percent to  [#permalink]

Show Tags

New post 03 Nov 2019, 09:40
10
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

72% (02:21) correct 28% (02:21) wrong based on 112 sessions

HideShow timer Statistics

Rabia must earn an average (arithmetic mean) score of S percent to pass her physics course. If her average score on the first 60 percent of her assignments was (S + 10) percent, and each of her assignments is weighted equally, then what is the maximum percentage below S that she can earn on her remaining assignments and still pass the course?

A) 10%
B) 15%
C) 20%
D) 85%
E) 90%
Senior Manager
Senior Manager
User avatar
D
Joined: 05 Jul 2018
Posts: 459
Location: India
Concentration: General Management, Technology
GMAT 1: 600 Q47 V26
GRE 1: Q162 V149
GPA: 3.6
WE: Information Technology (Consulting)
Reviews Badge
Re: Rabia must earn an average (arithmetic mean) score of S percent to  [#permalink]

Show Tags

New post 03 Nov 2019, 10:11
Let there be 10 exams in all.

She got S+10 average on 6 of them (60%)

\(\frac{(6*(S+10) + (Score-in-4-other-exams) )}{10}\) = S or higher to pass

\((Score-in-4-other-exams) =4S-60\)...Remember that this is all percentage we are dealing in

Minimum score on each of the 4 exams = \(\frac{(4S-60)}{4}\) = S-15

So the answer is 15%
Manager
Manager
User avatar
P
Status: So far only Dreams i have!!
Joined: 05 Jan 2015
Posts: 224
WE: Consulting (Consulting)
Premium Member Reviews Badge
Rabia must earn an average (arithmetic mean) score of S percent to  [#permalink]

Show Tags

New post Updated on: 03 Nov 2019, 22:29
My Approach:

Assume:
- Total exams = 10,
- S= 50%,
- Max Marks Per exam = 100
- X = maximum percentage below S to pass.


- Now, equation is: 6 * 60 + 4 * (S-X) = 10 * 50 (as she need S% to pass the exam)
=> 360 +4(S-X) = 500 => S-X = 140/4 = 35
50 - X = 35 => X = 15.

Option B
Please correct if my approach is wrong!
_________________
Unable to Give Up!

Originally posted by fauji on 03 Nov 2019, 11:59.
Last edited by fauji on 03 Nov 2019, 22:29, edited 1 time in total.
VP
VP
avatar
V
Joined: 20 Jul 2017
Posts: 1262
Location: India
Concentration: Entrepreneurship, Marketing
WE: Education (Education)
Re: Rabia must earn an average (arithmetic mean) score of S percent to  [#permalink]

Show Tags

New post 03 Nov 2019, 19:25
anmolmakkarz17 wrote:
Rabia must earn an average (arithmetic mean) score of S percent to pass her physics course. If her average score on the first 60 percent of her assignments was (S + 10) percent, and each of her assignments is weighted equally, then what is the maximum percentage below S that she can earn on her remaining assignments and still pass the course?

A) 10%
B) 15%
C) 20%
D) 85%
E) 90%


Let the total assignments = n
—> Her total score in 60% of tests = 0.6n*(S + 10)
Let her average score in remaining 40% tests = x
—> Total score = 0.4n*x

To just pass, average score = S
—> [0.6n(S + 10) + 0.4nx]/n = S
—> 0.6S + 6 + 0.4x = S
—> 0.4x = 0.4S - 6
—> x = (0.4S - 6)/0.4 = S - 60/4
—> x = S - 15

So, she can score a 15% less than her average to still pass the test

IMO Option B

Posted from my mobile device
GMAT Club Legend
GMAT Club Legend
User avatar
V
Joined: 12 Sep 2015
Posts: 4226
Location: Canada
Re: Rabia must earn an average (arithmetic mean) score of S percent to  [#permalink]

Show Tags

New post 05 Dec 2019, 07:41
Top Contributor
anmolmakkarz17 wrote:
Rabia must earn an average (arithmetic mean) score of S percent to pass her physics course. If her average score on the first 60 percent of her assignments was (S + 10) percent, and each of her assignments is weighted equally, then what is the maximum percentage below S that she can earn on her remaining assignments and still pass the course?

A) 10%
B) 15%
C) 20%
D) 85%
E) 90%


We can solve this question using weighted averages:
Weighted average of groups combined = (group A proportion)(group A average) + (group B proportion)(group B average) + (group C proportion)(group C average) + ...

Let x = the average percent score of the remaining 40% of Rabia's assignments
So, for this question, we can write: Average score = (60%)(S + 10) + (40%)(x)
Since we want the total average to be at least S, we can write: S = (60%)(S + 10) + (40%)(x)
Rewrite has: S = (0.6)(S + 10) + (0.4)(x)
Expand to get: S = 0.6S + 6 + 0.4x
Multiply both sides by 10 to get: 10S = 6S + 60 + 4x
Subtract 6S from both sides by 10 to get: 4S = 60 + 4x
Subtract 60 from both sides to get: 4S - 60 = 4x
Divide both sides by 4 to get: S - 15 = x
So, we need an average score of S - 15 on the remaining 40% of the assignments to ensure that Rabia gets a total score of S.

The question asks "What is the maximum percentage below S that she can earn on her remaining assignments and still pass the course?"
Answer: 15 = B


Cheers,
Brent
_________________
Test confidently with gmatprepnow.com
Image
EMPOWERgmat Instructor
User avatar
V
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 15975
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: Rabia must earn an average (arithmetic mean) score of S percent to  [#permalink]

Show Tags

New post 06 Dec 2019, 15:46
Hi All,

We're told that Rabia must earn an AVERAGE (arithmetic mean) score of S percent to pass her physics course, the average score on the first 60 percent of her assignments was (S + 10) percent, and each of her assignments is weighted equally. We're asked for the MAXIMUM percentage BELOW S that she can earn on her remaining assignments and still pass the course. Since this is a 'ratio' question, it can be approached in a number of different ways, including by TESTing VALUES.

Since 60% is 3/5, we can start by saying that there are 5 total assignments.
Let's also TEST S = 70, meaning that Rabia needs an average of 70% over the 5 assignments to pass.

On the first 3 of those assignments, she averaged (70+10) = 80 percent.... In simple terms, she needs 5(70) = 350 points and she already has 3(80) = 240 points. To put it another way, she is 3(10) = 30 points AHEAD of what she needs to pass the course. She would need another 350 - 240 = 110 points to pass.

With 2 assignments remaining, she would need to average 110/2 = 55 points to pass. That is 70 - 55 = 15 points BELOW S.

Final Answer:

GMAT assassins aren't born, they're made,
Rich
_________________
Contact Rich at: Rich.C@empowergmat.com
Image


The Course Used By GMAT Club Moderators To Earn 750+

souvik101990 Score: 760 Q50 V42 ★★★★★
ENGRTOMBA2018 Score: 750 Q49 V44 ★★★★★
GMAT Club Bot
Re: Rabia must earn an average (arithmetic mean) score of S percent to   [#permalink] 06 Dec 2019, 15:46
Display posts from previous: Sort by

Rabia must earn an average (arithmetic mean) score of S percent to

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





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne