GMAT Changed on April 16th - Read about the latest changes here

It is currently 22 Apr 2018, 01:36

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

Events & Promotions in June
Open Detailed Calendar

Eight boxes, weighing an average of 12.75 kilograms, and 12 boxes, wei

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

Hide Tags

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 44599
Eight boxes, weighing an average of 12.75 kilograms, and 12 boxes, wei [#permalink]

Show Tags

New post 26 Mar 2018, 00:34
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

92% (01:23) correct 8% (01:03) wrong based on 25 sessions

HideShow timer Statistics

Eight boxes, weighing an average of 12.75 kilograms, and 12 boxes, weighing an average of 15.25 kilograms, are shipped to the same location. What is the average weight, in kilograms, of the 20 boxes shipped to the location?

(A) 13
(B) 13.25
(C) 14
(D) 14.25
(E) 15
[Reveal] Spoiler: OA

_________________

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

BSchool Forum Moderator
User avatar
V
Joined: 26 Feb 2016
Posts: 2435
Location: India
GPA: 3.12
Premium Member CAT Tests
Eight boxes, weighing an average of 12.75 kilograms, and 12 boxes, wei [#permalink]

Show Tags

New post 26 Mar 2018, 01:12
Bunuel wrote:
Eight boxes, weighing an average of 12.75 kilograms, and 12 boxes, weighing an average of 15.25 kilograms, are shipped to the same location. What is the average weight, in kilograms, of the 20 boxes shipped to the location?

(A) 13
(B) 13.25
(C) 14
(D) 14.25
(E) 15



We know 1.25 = \(\frac{5}{4}\). Hence \(\frac{5}{4}*8 = 10\) and \(\frac{5}{4}*12 = 15\)

Average = \(\frac{(14 - 1.25)*8 + (14 + 1.25)*12}{20} = \frac{14*20 - 10 + 15}{20} = 14 + \frac{5}{20} = 14.25\)

Therefore, the average of 20 boxes shipped is 14.25(Option D)
P.S In order to solve problems such as these, it is important to identify a pattern to reduce unnecessary calculations.
_________________

Stay hungry, Stay foolish

2017-2018 MBA Deadlines

Class of 2020: Rotman Thread | Schulich Thread
Class of 2019: Sauder Thread

Manager
Manager
User avatar
G
Joined: 16 Sep 2016
Posts: 207
WE: Analyst (Health Care)
Re: Eight boxes, weighing an average of 12.75 kilograms, and 12 boxes, wei [#permalink]

Show Tags

New post 26 Mar 2018, 01:46
pushpitkc wrote:
Bunuel wrote:
Eight boxes, weighing an average of 12.75 kilograms, and 12 boxes, weighing an average of 15.25 kilograms, are shipped to the same location. What is the average weight, in kilograms, of the 20 boxes shipped to the location?

(A) 13
(B) 13.25
(C) 14
(D) 14.25
(E) 15



We know 1.25 = \(\frac{5}{4}\). Hence \(\frac{5}{4}*8 = 10\) and \(\frac{5}{4}*12 = 15\)

Average = \(\frac{(14 - 1.25)*8 + (14 + 1.25)*12}{20} = \frac{14*20 - 10 + 15}{20} = 14 + \frac{5}{20} = 14.25\)

Therefore, the average of 20 boxes shipped is 14.25(Option D)

P.S In order to solve problems such as these, it is important to identify a pattern to reduce unnecessary calculations.


Great way to simplify this pushpitkc,

Another way to look at it is -

\(12.75 = 12 \frac{3}{4} improper fraction ... (12*4 +3 )/4 = 51/4\)
\(15.25 = 15 \frac{1}{4} = 61/4\)

Numerator is : \(\frac{51}{4}* 8 + \frac{61}{4}*3 = 50*2 + 60*3 + 2 + 3 = 285\)

On dividing by 20 .. which is 10 * 2

Divide by 2 first and move decimals point one to the left.

Hence \(285 / 2 = 142.5 / 10 = 14.25\)

Hence Option (D) is correct.

Always try to simplify the calculations as much as possible...

Best,
Gladi
Director
Director
User avatar
P
Status: It's near - I can see.
Joined: 13 Apr 2013
Posts: 710
Location: India
Concentration: International Business, Operations
GMAT 1: 480 Q38 V22
GPA: 3.01
WE: Engineering (Consulting)
Premium Member Reviews Badge
Re: Eight boxes, weighing an average of 12.75 kilograms, and 12 boxes, wei [#permalink]

Show Tags

New post 26 Mar 2018, 09:28
Bunuel wrote:
Eight boxes, weighing an average of 12.75 kilograms, and 12 boxes, weighing an average of 15.25 kilograms, are shipped to the same location. What is the average weight, in kilograms, of the 20 boxes shipped to the location?

(A) 13
(B) 13.25
(C) 14
(D) 14.25
(E) 15


\(\frac{(8*12 + 8*0.75) + (12*15 + 12*0.25)}{(8 + 20)}\)

\(\frac{96 + 6 + 180 + 3}{20}\)

\(\frac{285}{20}\)

\(14.25\)

(D)
_________________

"Success is not as glamorous as people tell you. It's a lot of hours spent in the darkness."

Expert Post
Target Test Prep Representative
User avatar
G
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 2447
Location: United States (CA)
Re: Eight boxes, weighing an average of 12.75 kilograms, and 12 boxes, wei [#permalink]

Show Tags

New post 28 Mar 2018, 10:34
Bunuel wrote:
Eight boxes, weighing an average of 12.75 kilograms, and 12 boxes, weighing an average of 15.25 kilograms, are shipped to the same location. What is the average weight, in kilograms, of the 20 boxes shipped to the location?

(A) 13
(B) 13.25
(C) 14
(D) 14.25
(E) 15


The total weight of the 20 boxes is:

12.75 x 8 + 15.25 x 12 = 102 + 183 = 285 kg

The average is 285/20 = 14.25 kg.

Answer: D
_________________

Scott Woodbury-Stewart
Founder and CEO

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

Re: Eight boxes, weighing an average of 12.75 kilograms, and 12 boxes, wei   [#permalink] 28 Mar 2018, 10:34
Display posts from previous: Sort by

Eight boxes, weighing an average of 12.75 kilograms, and 12 boxes, wei

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


GMAT Club MBA Forum Home| About| Terms and Conditions| 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®.