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

It is currently 17 Jan 2019, 19:43

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 January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
  • The winning strategy for a high GRE score

     January 17, 2019

     January 17, 2019

     08:00 AM PST

     09:00 AM PST

    Learn the winning strategy for a high GRE score — what do people who reach a high score do differently? We're going to share insights, tips and strategies from data we've collected from over 50,000 students who used examPAL.
  • Free GMAT Strategy Webinar

     January 19, 2019

     January 19, 2019

     07:00 AM PST

     09:00 AM PST

    Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

An instructor gave the same test to three groups: P, Q, and R. The ave

  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: 52231
An instructor gave the same test to three groups: P, Q, and R. The ave  [#permalink]

Show Tags

New post 25 Sep 2018, 03:57
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

92% (01:40) correct 8% (03:54) wrong based on 26 sessions

HideShow timer Statistics

An instructor gave the same test to three groups: P, Q, and R. The average (arithmetic mean) scores for the three groups were 64, 84, and 72, respectively. The ratio of the numbers of candidates in each class who took the test was 3 : 5 : 4, respectively. What was the average score for the three groups combined?

(A) 72
(B) 75
(C) 77
(D) 78
(E) 80

_________________

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

Manager
Manager
avatar
B
Joined: 19 Apr 2017
Posts: 52
An instructor gave the same test to three groups: P, Q, and R. The ave  [#permalink]

Show Tags

New post 29 Sep 2018, 21:52
Sum=N*Mean

Sum of P=3x*64
Sum of Q=5x*84
Sum of R=4x*72

If you keep calculations till the end for sum problems you could save time

Sum of all three groups = \(3x*64+5x*84+4x*72\)
Total members in all three group=\(n = 3x+5x+4x = 12x\)

Mean of all three group = Sum/n = \(3x/12x*64+5x/12x*84+4x/12x*72 = 16+35+24\) = 75 = Answer B
Director
Director
User avatar
G
Joined: 20 Feb 2015
Posts: 795
Concentration: Strategy, General Management
Premium Member
Re: An instructor gave the same test to three groups: P, Q, and R. The ave  [#permalink]

Show Tags

New post 29 Sep 2018, 22:30
Bunuel wrote:
An instructor gave the same test to three groups: P, Q, and R. The average (arithmetic mean) scores for the three groups were 64, 84, and 72, respectively. The ratio of the numbers of candidates in each class who took the test was 3 : 5 : 4, respectively. What was the average score for the three groups combined?

(A) 72
(B) 75
(C) 77
(D) 78
(E) 80


\(\frac{(3*64 + 5*84 + 4*72)}{12}\) = (16 + 7*5 + 4*6) = 75
B
GMAT Club Bot
Re: An instructor gave the same test to three groups: P, Q, and R. The ave &nbs [#permalink] 29 Sep 2018, 22:30
Display posts from previous: Sort by

An instructor gave the same test to three groups: P, Q, and R. The ave

  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®.