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

 It is currently 23 Jan 2020, 13:05

### 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

# 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =

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

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 60627
1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =  [#permalink]

### Show Tags

Updated on: 23 Jun 2018, 12:02
5
11
00:00

Difficulty:

5% (low)

Question Stats:

95% (00:57) correct 5% (02:02) wrong based on 1553 sessions

### HideShow timer Statistics

$$\frac{1}{3} + \frac{1}{2} - \frac{5}{6} + \frac{1}{5} + \frac{1}{4} - \frac{9}{20} =$$

A. $$0$$

B. $$\frac{2}{15}$$

C. $$\frac{2}{5}$$

D. $$\frac{9}{20}$$

E. $$\frac{5}{6}$$

Kudos for a correct solution.

_________________

Originally posted by Bunuel on 14 Oct 2015, 21:15.
Last edited by carcass on 23 Jun 2018, 12:02, edited 1 time in total.
Formatted
##### Most Helpful Community Reply
Intern
Joined: 24 Aug 2015
Posts: 41
Location: Spain
Concentration: General Management, Technology
GMAT 1: 750 Q49 V42
GPA: 3.5
WE: Management Consulting (Consulting)
Re: 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =  [#permalink]

### Show Tags

15 Oct 2015, 02:12
10
Even though it could be tempting to find the common denominator (60), and operate, the way the terms are ordered is inviting us to group the first and last three terms -common denominator (6 and 20 respectively)- to operate more easily:

Doing this, we can rewrite the given expression as

$$1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 = A + B$$, where

$$A = 1/3 +1/2 - 5/6 = 2/6 + 3/6 - 5/6 = 0$$

$$B = 1/5 + 1/4 - 9/20 = 4/20 + 5/20 – 9/20 = 0$$

Thus, $$1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 = 0 + 0 = 0$$

Answer: A
##### General Discussion
Retired Moderator
Joined: 29 Oct 2013
Posts: 248
Concentration: Finance
GPA: 3.7
WE: Corporate Finance (Retail Banking)
Re: 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =  [#permalink]

### Show Tags

11 Dec 2015, 03:10
1
Remember for addition/subtraction its easier to work with decimals. we all should have these fraction memorized for decimal values-

.33+.5-.83+.2+.25-.45=0
_________________
Please contact me for super inexpensive quality private tutoring

My journey V46 and 750 -> http://gmatclub.com/forum/my-journey-to-46-on-verbal-750overall-171722.html#p1367876
GMAT Club Legend
Joined: 12 Sep 2015
Posts: 4226
Location: Canada
Re: 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =  [#permalink]

### Show Tags

11 Apr 2016, 10:39
Related Resources
The following free videos cover the concepts/strategies that are useful for answering this question:

Cheers,
Brent
_________________
Test confidently with gmatprepnow.com
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 9117
Location: United States (CA)
Re: 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =  [#permalink]

### Show Tags

03 May 2016, 08:51
2
Bunuel wrote:
1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =

A. 0
B. 2/15
C. 2/5
D. 9/20
E. 5/6

Kudos for a correct solution.

Solution:

We need to determine the result of 1/3 + 1/2 - 5/6 + 1/5 + 1/4 - 9/20

Let’s add the given fractions in two groups. In the group of the first three fractions, notice that 1/3 and 1/2 share a common denominator of 6 with 5/6.

1/2 + 1/3 = 3/6 + 2/6 = 5/6

Thus, 5/6 – 5/6 = 0

Looking at the 2nd group of the fractions (1/5, 1/4, and 9/20), notice that 1/5 and 1/4 share a common denominator of 20 with 9/20.

1/5 + 1/4 = 4/20 + 5/20 = 9/20

Thus, 9/20 – 9/20 = 0.

Thus, the result of 1/3 + 1/2 – 5/6 + 1/5 + 1/4 – 9/20 is 0.

Answer: A
_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
181 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

Senior Manager
Joined: 11 Nov 2014
Posts: 305
Location: India
Concentration: Finance, International Business
WE: Project Management (Telecommunications)
Re: 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =  [#permalink]

### Show Tags

08 May 2016, 06:02
I got D

solved bit by bit
1/3 +1/2 = 5/6 -
5/6+1/5+1/4 = 125/120 -
9/20

100-152-54/120 = -9/20
I know I answered incorrectly, but why did I falter?
Math Expert
Joined: 02 Aug 2009
Posts: 8335
Re: 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =  [#permalink]

### Show Tags

08 May 2016, 06:24
paidlukkha wrote:
I got D

solved bit by bit
1/3 +1/2 = 5/6 -
5/6+1/5+1/4 = 125/120 -
9/20

100-152-54/120 = -9/20
I know I answered incorrectly, but why did I falter?

you are wrong in highlighted portion..
the highlighted portion is -5/6 +1/4+1/2 and you have worked for -(5/6+1/4+1/2)..
..
You can add all those with - sign together , here -(5/6+9/20)..
and all those with +sign...
- sign before 5/6 is ONLY for 5/6 and not for all terms after that..
_________________
Senior Manager
Joined: 11 Nov 2014
Posts: 305
Location: India
Concentration: Finance, International Business
WE: Project Management (Telecommunications)
Re: 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =  [#permalink]

### Show Tags

08 May 2016, 06:29
chetan2u wrote:
paidlukkha wrote:
I got D

solved bit by bit
1/3 +1/2 = 5/6 -
5/6+1/5+1/4 = 125/120 -
9/20

100-152-54/120 = -9/20
I know I answered incorrectly, but why did I falter?

you are wrong in highlighted portion..
the highlighted portion is -5/6 +1/4+1/2 and you have worked for -(5/6+1/4+1/2)..
..
You can add all those with - sign together , here -(5/6+9/20)..
and all those with +sign...
- sign before 5/6 is ONLY for 5/6 and not for all terms after that..

every time I have this bracket issue
Which topic should I revise?

also for x(sq)=36, so x = 6/-6
but underroot 36, in GMAT is only 6 & -6 is not valid
Board of Directors
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4860
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)
Re: 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =  [#permalink]

### Show Tags

08 May 2016, 06:32
paidlukkha wrote:
I got D

solved bit by bit
1/3 +1/2 = 5/6 -
5/6+1/5+1/4 = 125/120 -
9/20

100-152-54/120 = -9/20
I know I answered incorrectly, but why did I falter?

Ok , Would like to highlight the same here -

1/3 +1/2 = 5/6 - 5/6 => 0

1/5+1/4 = 9/20 -9/20 => 0

There is something interesting to notice here

(1/3 +1/2 - 5/6 ) + (1/5 + 1/4 - 9/20)

(5/6 - 5/6 ) + (9/20 - 9/20)

The red highlighted part is the sum of its previous terms and is -ve that makes the result zero..

Hope this helps !! :-D
_________________
Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )
Current Student
Joined: 18 Oct 2014
Posts: 791
Location: United States
GMAT 1: 660 Q49 V31
GPA: 3.98
Re: 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =  [#permalink]

### Show Tags

08 May 2016, 08:59
1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20

I found it easy to solve by taking LCM (Fractions always look nasty to me )

20+30 -50 +12 +15 -27/60

Just by looking at the numerator I figured out that answer will be '0'
_________________
I welcome critical analysis of my post!! That will help me reach 700+
Manager
Joined: 27 Dec 2016
Posts: 224
Concentration: Marketing, Social Entrepreneurship
GPA: 3.65
WE: Marketing (Education)
Re: 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =  [#permalink]

### Show Tags

28 Aug 2017, 09:24
Bunuel wrote:
1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =

A. 0
B. 2/15
C. 2/5
D. 9/20
E. 5/6

Kudos for a correct solution.

- Find the LCM for denominator --> we find 60.
- Convert all of the fraction into 60 in denominator --> $$\frac{(1*20)+(1*30)-(5*10)+(1*12)+(1*15)-(9*3)}{60}$$ --> All of numerator cancelled out, so we can write it $$\frac{0}{60}$$ which is 0.

A.
_________________
There's an app for that - Steve Jobs.
Intern
Joined: 04 Sep 2018
Posts: 27
GPA: 3.33
Re: 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =  [#permalink]

### Show Tags

14 Nov 2018, 11:16
Is finding a common denominator first, and doing the arithmetic a good way to approach this question?

Novice to the gmat and only started, so just want to know if I did it in an efficient manner, or should I learn other ways which take less time?

Thanks.
Manager
Joined: 01 Mar 2015
Posts: 67
Re: 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =  [#permalink]

### Show Tags

14 Nov 2018, 14:47
nust2017 wrote:
Is finding a common denominator first, and doing the arithmetic a good way to approach this question?

Novice to the gmat and only started, so just want to know if I did it in an efficient manner, or should I learn other ways which take less time?

Thanks.

Finding common denominator for all terms is not a good way to solve this type of problems.

Grouping the terms by recognising the terms with common/similar denominator and solving them separately saves lot of time by avoiding lengthy calculations.
We can see this as explained in above solutions.

Posted from my mobile device
Intern
Joined: 25 Dec 2018
Posts: 14
Location: India
Concentration: Technology, Real Estate
WE: Business Development (Computer Software)
Re: 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =  [#permalink]

### Show Tags

02 Apr 2019, 18:46
v12345 wrote:
nust2017 wrote:
Is finding a common denominator first, and doing the arithmetic a good way to approach this question?

Novice to the gmat and only started, so just want to know if I did it in an efficient manner, or should I learn other ways which take less time?

Thanks.

Finding common denominator for all terms is not a good way to solve this type of problems.

Grouping the terms by recognising the terms with common/similar denominator and solving them separately saves lot of time by avoiding lengthy calculations.
We can see this as explained in above solutions.

Posted from my mobile device

Agreed. My first instinct was to solve by taking lcm of all and took me around 3 minutes.
Manager
Joined: 24 Sep 2018
Posts: 117
Location: India
Re: 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =  [#permalink]

### Show Tags

15 Jul 2019, 02:24
1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =

first take all the positive one side and negative one side

1/3+1/2+1/5+1/4-5/6-9/20
1/3+1/2+1/5+1/4-(5/6+9/20)
77/60 - 77/60 =0
SVP
Joined: 03 Jun 2019
Posts: 1941
Location: India
GMAT 1: 690 Q50 V34
Re: 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =  [#permalink]

### Show Tags

16 Sep 2019, 08:53
Bunuel wrote:
$$\frac{1}{3} + \frac{1}{2} - \frac{5}{6} + \frac{1}{5} + \frac{1}{4} - \frac{9}{20} =$$

A. $$0$$

B. $$\frac{2}{15}$$

C. $$\frac{2}{5}$$

D. $$\frac{9}{20}$$

E. $$\frac{5}{6}$$

Kudos for a correct solution.

$$\frac{1}{3} + \frac{1}{2} - \frac{5}{6} + \frac{1}{5} + \frac{1}{4} - \frac{9}{20} =$$
$$\frac{1}{3} + \frac{1}{2} - \frac{5}{6} = 0$$
$$\frac{1}{5} + \frac{1}{4} - \frac{9}{20} = 0$$
$$\frac{1}{3} + \frac{1}{2} - \frac{5}{6} + \frac{1}{5} + \frac{1}{4} - \frac{9}{20} = 0 + 0 = 0$$

IMO A
Re: 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =   [#permalink] 16 Sep 2019, 08:53
Display posts from previous: Sort by

# 1/3 +1/2 - 5/6 + 1/5 + 1/4 - 9/20 =

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

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