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

It is currently 13 Dec 2018, 07:41

R1 Admission Decisions:

Stanford Chat (Calls Started)  |  Wharton Chat  (Calls Expected Soon)  |  Fuqua Chat (Calls Expected Soon)


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 in December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
  • The winning strategy for 700+ on the GMAT

     December 13, 2018

     December 13, 2018

     08:00 AM PST

     09:00 AM PST

    What people who reach the high 700's do differently? We're going to share insights, tips and strategies from data we collected on over 50,000 students who used examPAL.
  • GMATbuster's Weekly GMAT Quant Quiz, Tomorrow, Saturday at 9 AM PST

     December 14, 2018

     December 14, 2018

     09:00 AM PST

     10:00 AM PST

    10 Questions will be posted on the forum and we will post a reply in this Topic with a link to each question. There are prizes for the winners.

The table above shows the closing price of a stock during a week. If

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

Hide Tags

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51185
The table above shows the closing price of a stock during a week. If  [#permalink]

Show Tags

New post 12 Oct 2017, 23:18
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

93% (01:34) correct 7% (02:13) wrong based on 57 sessions

HideShow timer Statistics

Image
The table above shows the closing price of a stock during a week. If the average (arithmetic mean) closing price for the five days was $75.50, what was the closing price on Friday?

A. $75.35
B. $75.40
C. $75.42
D. $75.45
E. $75.48

Attachment:
2017-10-13_1116.png
2017-10-13_1116.png [ 9.74 KiB | Viewed 945 times ]

_________________

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

Senior Manager
Senior Manager
User avatar
P
Joined: 07 Jul 2012
Posts: 378
Location: India
Concentration: Finance, Accounting
GPA: 3.5
Premium Member CAT Tests
Re: The table above shows the closing price of a stock during a week. If  [#permalink]

Show Tags

New post 13 Oct 2017, 00:00
1
Let the Closing price on Friday= x

\(\frac{75.58+75.63+75.42+75.52+x}{5}\)= 75.50

\(\frac{302.15+x}{5}\)= 75.50

302.15+x= 377.50
x= 377.50-302.15= 75.35
x= 75.35

Answer: A.

Kudos please if you like my explanation!
_________________

Kindly hit kudos if my post helps!

Intern
Intern
User avatar
B
Joined: 10 Apr 2017
Posts: 38
Schools: Kelley '20
Re: The table above shows the closing price of a stock during a week. If  [#permalink]

Show Tags

New post 13 Oct 2017, 00:42
Here,
Let the Closing price on Friday= x

75.58+75.63+75.42+75.52+x575.58+75.63+75.42+75.52+x5= 75.50

302.15+x5302.15+x5= 75.50

302.15+x= 377.50
x= 377.50-302.15= 75.35
x= 75.35

Answer: A.
Intern
Intern
avatar
B
Joined: 15 Aug 2012
Posts: 42
Schools: AGSM '19
GMAT ToolKit User CAT Tests
The table above shows the closing price of a stock during a week. If  [#permalink]

Show Tags

New post 14 Oct 2017, 15:54
1
Another approach I've come to admire for these kind of questions.

Think how far off each of these amounts are from the Mean.

Monday: 75.58 --> Exceeds mean by 0.08
Tuesday: 75.63 --> Exceeds mean by 0.13
Wednesday: 75.42 --> Fall shorts from mean by 0.08
Thursday: 75.52 --> Exceeds mean by 0.02

Excess: 0.08 + 0.13 + 0.02 = 0.23
Short: 0.08

Excess > Short; So right now the sum of these 4 amounts exceed the Mean by 0.15 (0.23 - 0.08)

Our 5th amount should be something that compensates for the excess i.e. it should be 0.15 less than Mean which brings us to
75.35

This method has minimal calculations meaning fewer chances you mess up during calculations.

Don't forget the kudos if this helped ya!
Intern
Intern
User avatar
B
Joined: 29 May 2012
Posts: 36
Premium Member
Re: The table above shows the closing price of a stock during a week. If  [#permalink]

Show Tags

New post 14 Oct 2017, 18:12
1. Calculate the variance between each number and the mean.

- Variance between 75.58 and the mean (75.5) is +0.08
- Variance between 75.63 and the mean (75.5) is +0.13
- Variance between 75.42 and the mean (75.5) is -0.08
- Variance between 75.52 and the mean (75.5) is +0.02

2. Let the variance between the closing price on Friday and the mean be x

3. 0.08+0.13-0.08+0.02+x=0
Then x=-0.15

4. So the Closing Price on Friday is:
Mean + Variance = 75.5+(-0.15) = 75.35

Answer is A
Target Test Prep Representative
User avatar
G
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2830
Re: The table above shows the closing price of a stock during a week. If  [#permalink]

Show Tags

New post 16 Oct 2017, 16:20
Bunuel wrote:
Image
The table above shows the closing price of a stock during a week. If the average (arithmetic mean) closing price for the five days was $75.50, what was the closing price on Friday?

A. $75.35
B. $75.40
C. $75.42
D. $75.45
E. $75.48

Attachment:
2017-10-13_1116.png


We can let x = the closing price on Friday, and thus:

(75.58 + 75.63 + 75.42 + 75.52 + x)/5 = 75.50

(302.15 + x)/5 = 75.50

302.15 + x = 377.50

x = 75.35

Alternate Solution:

Since we are given that the average for the five days was 75.50, let’s compare each of the four given days to the average.

Mon Tues Wed Thurs
+0.08 +0.13 -0.08 +0.02
Notice that +0.08 will cancel with -0.08; therefore, the total net gain from the 4 days is +0.15. Thus, we must have -0.15 on Friday to counter the net gain of +0.15, and so the closing price on Friday must be 75.50 - 0.15 = 75.35. (Note: When a list of numbers is given (but one of them is missing) and the average of the numbers is given, this method of finding the missing number is most useful when the given numbers are pretty close to the average.)

Answer: A
_________________

Jeffery Miller
Head of GMAT Instruction

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

GMAT Club Bot
Re: The table above shows the closing price of a stock during a week. If &nbs [#permalink] 16 Oct 2017, 16:20
Display posts from previous: Sort by

The table above shows the closing price of a stock during a week. If

  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®.