NEW HERE? LEARN MORE
closeclose
Last visit was: 24 Apr 2024, 05:12 It is currently 24 Apr 2024, 05:12
Decision Tracker
My Rewards
New posts
New comers' posts

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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

There are 12 workers who have been recruited to dig a 20 km long tunn

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92901
Own Kudos [?]: 618718 [0]
Given Kudos: 81586
Send PM
CAT Tests Forum Quiz Mode
There are 12 workers who have been recruited to dig a 20 km long tunn [#permalink] New post   21 Jun 2021, 08:45
Expert Reply
00:00
A
B
C
D
E

Difficulty:

25% (medium)

Question Stats:

73% (01:54) correct 27% (02:20) wrong based on 55 sessions
Hide Show timer Statistics
There are 12 workers who have been recruited to dig a 20 km long tunnel. It takes one worker to dig 250 m of tunnel in a week. How many more workers are needed to complete the work in 2 weeks?

(A) 12
(B) 18
(C) 20
(D) 24
(E) 28
ShowHide Answer
Official Answer
E
User avatar
L
Kinshook
GMAT Club Legend
GMAT Club Legend
Joined: 03 Jun 2019
Posts: 5343
Own Kudos [?]: 3964 [0]
Given Kudos: 160
Location: India
Schools: HBS '22 CBS '22 Wharton '22
GMAT 1: 690 Q50 V34
WE:Engineering (Transportation)
Send PM
Reviews Badge
Re: There are 12 workers who have been recruited to dig a 20 km long tunn [#permalink] New post   21 Jun 2021, 09:44
Given: There are 12 workers who have been recruited to dig a 20 km long tunnel. It takes one worker to dig 250 m of tunnel in a week.
Asked: How many more workers are needed to complete the work in 2 weeks?

1 worker takes 1 week to dig 250m of tunnel
80 workers will take 1 week to dig 250*80 = 20000 m = 20 km long tunnel
40 workers will take 2 weeks to dig 20 km long tunnel
Since 12 workers have already been recruited, 40-12= 28 more workers will be needed.

IMO E
User avatar
L
GMATWhizTeam
GMATWhiz Representative
Joined: 07 May 2019
Posts: 3409
Own Kudos [?]: 1800 [0]
Given Kudos: 68
Location: India
GMAT 1: 740 Q50 V41
GMAT 2: 760 Q51 V40
Send PM
Re: There are 12 workers who have been recruited to dig a 20 km long tunn [#permalink] New post   21 Jun 2021, 09:59
Expert Reply
Solution:

It is given that:
\(1\) worker will take \(1\) week to dig \(250\)m
So, \(1\) worker will tale \(2\) weeks to dig \(500\times 2=250=500\)m
Or, \(\frac{1}{500}\) workers will take \(2\) weeks to dig \(1\)m
Or, \(\frac{1}{500}\times 20000\) workers will take \(2\) weeks to dig \(20000\)m
Or, \(40\) workers will take \(2\) weeks to dig \(20000\)m or \(20\)km

So, to dig \(20\)km in \(2\) weeks, \(40\) workers will be needed.
\(12\) workers are already recruited. Thus, more \(28\) workers will be needed.

Hence the right answer is Option E.
User avatar
L
CrackverbalGMAT
GMAT Club Legend
GMAT Club Legend
Joined: 03 Oct 2013
Affiliations: CrackVerbal
Posts: 4946
Own Kudos [?]: 7625 [0]
Given Kudos: 215
Location: India
Send PM
Re: There are 12 workers who have been recruited to dig a 20 km long tunn [#permalink] New post   21 Jun 2021, 12:17
Top Contributor
Solution:

Use M1D1/W1 = M2D2/W2

=> 1 * 1/250 = M2 * 2/20000

=>M2 = 20,000/500 = 40 workers

=>Number of additional workers =40-12 = 28 workers (option e)


-Stay focused on the goal-
Devmitra Sen
GMAT SME
avatar
B
juliustp
Intern
Intern
Joined: 25 Nov 2020
Posts: 2
Own Kudos [?]: 0 [0]
Given Kudos: 27
Send PM
Re: There are 12 workers who have been recruited to dig a 20 km long tunn [#permalink] New post   21 Jun 2021, 13:49
Solution:
Total work 20km
1000m=1km so 20km = 20000m
So 20000m/250m= 12workers + x workers/1worker* 2weeks/1week
= 80m= 24+2x
80-24=2x
Therefore, 56=2x
x= 56/2= 28(answer E)

Posted from my mobile device
GMAT Club Bot
gmatclubot
Re: There are 12 workers who have been recruited to dig a 20 km long tunn [#permalink]
21 Jun 2021, 13:49
Moderators:
Bunuel
Math Expert
92901 posts
yashikaaggarwal
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions