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

 It is currently 20 Feb 2019, 16:45

### 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

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

## Events & Promotions

###### Events & Promotions in February
PrevNext
SuMoTuWeThFrSa
272829303112
3456789
10111213141516
17181920212223
242526272812
Open Detailed Calendar
• ### Free GMAT Prep Hour

February 20, 2019

February 20, 2019

08:00 PM EST

09:00 PM EST

Strategies and techniques for approaching featured GMAT topics. Wednesday, February 20th at 8 PM EST

February 21, 2019

February 21, 2019

10:00 PM PST

11:00 PM PST

Kick off your 2019 GMAT prep with a free 7-day boot camp that includes free online lessons, webinars, and a full GMAT course access. Limited for the first 99 registrants! Feb. 21st until the 27th.

# A does half as much work as B in three-fourth of the time. If together

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 53020
A does half as much work as B in three-fourth of the time. If together  [#permalink]

### Show Tags

30 Jan 2019, 01:59
00:00

Difficulty:

45% (medium)

Question Stats:

60% (02:15) correct 40% (03:04) wrong based on 36 sessions

### HideShow timer Statistics

A does half as much work as B in three-fourth of the time. If together they take 18 days to complete the work, how much time shall B take to do it

A. 40 days
B. 35 days
C. 30 days
D. 25 days
E. 20 days

_________________
SVP
Joined: 18 Aug 2017
Posts: 1887
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
Re: A does half as much work as B in three-fourth of the time. If together  [#permalink]

### Show Tags

30 Jan 2019, 02:33
Bunuel wrote:
A does half as much work as B in three-fourth of the time. If together they take 18 days to complete the work, how much time shall B take to do it

A. 40 days
B. 35 days
C. 30 days
D. 25 days
E. 20 days

for A given
work
x/2 = 3/4 * ra
ra = 2x/3
rb= x

given together a & b can do work in 18 days
or say
2x/3 + x= 1/18
5x=1/6
x= 1/30
days of b = 30 days
IMO C
_________________

If you liked my solution then please give Kudos. Kudos encourage active discussions.

Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 4938
Location: United States (CA)
Re: A does half as much work as B in three-fourth of the time. If together  [#permalink]

### Show Tags

01 Feb 2019, 18:12
Bunuel wrote:
A does half as much work as B in three-fourth of the time. If together they take 18 days to complete the work, how much time shall B take to do it

A. 40 days
B. 35 days
C. 30 days
D. 25 days
E. 20 days

We can let n = the number of days it takes B to complete the work by himself. Thus, B’s rate = 1/n and A’s rate = (1/2)/(3n/4) = 4/(6n) = 2/(3n). The sum of their individual rates is 1/18, and we create the equation:

2/(3n) + 1/n = 1/18

Multiplying by 18n, we have:

12 + 18 = n

30 = n

So it takes B 30 days to complete the job by himself.

_________________

Scott Woodbury-Stewart
Founder and CEO

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

VP
Joined: 07 Dec 2014
Posts: 1153
Re: A does half as much work as B in three-fourth of the time. If together  [#permalink]

### Show Tags

01 Feb 2019, 20:09
Bunuel wrote:
A does half as much work as B in three-fourth of the time. If together they take 18 days to complete the work, how much time shall B take to do it

A. 40 days
B. 35 days
C. 30 days
D. 25 days
E. 20 days

B's time to complete work alone=t
A's rate=(1/2)/(3t/4)=2/3t
18(2/3t+1/t)=1
t=30 days
C
Re: A does half as much work as B in three-fourth of the time. If together   [#permalink] 01 Feb 2019, 20:09
Display posts from previous: Sort by