Last visit was: 23 May 2024, 06:20 It is currently 23 May 2024, 06:20
Toolkit
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
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

# X takes 10 days to complete a task. Y takes half that time

SORT BY:
Tags:
Show Tags
Hide Tags
SVP
Joined: 24 Nov 2016
Posts: 1717
Own Kudos [?]: 1349 [0]
Given Kudos: 607
Location: United States
GMAT Club Legend
Joined: 03 Jun 2019
Posts: 5350
Own Kudos [?]: 4016 [0]
Given Kudos: 160
Location: India
GMAT 1: 690 Q50 V34
WE:Engineering (Transportation)
Manager
Joined: 26 Jul 2020
Posts: 206
Own Kudos [?]: 156 [0]
Given Kudos: 67
Intern
Joined: 09 Apr 2020
Posts: 6
Own Kudos [?]: 1 [0]
Given Kudos: 184
Re: X takes 10 days to complete a task. Y takes half that time [#permalink]
please explain... i am getting ans as 2 i.e. option A
Intern
Joined: 24 Aug 2020
Posts: 5
Own Kudos [?]: 0 [0]
Given Kudos: 14
Re: X takes 10 days to complete a task. Y takes half that time [#permalink]
SVaidyaraman wrote:
X takes 10 days to complete a task. Y takes half that time to complete the same task. X starts working on the task and later Y joins X. Both work on the task together and complete the task. If 40% of the total work is done by X, for how many days did X and Y work together?

A. 2
B. 3
C. 4
D. 5
E. 6

X done 40% of work and remaining work will gonna done by X and Y both.
Since the efficiency of X:Y is 1:2.
So the remaining 60% work will also gonna complete in 1:2 ratio.
That means 20% of work will done by X and 40% will done by Y in perticular time.

Since X require 10 days to complete 100% work, so he will need 2 days to complete remaining 20% of work and so does Y, to complete 40% of remaining work.

Posted from my mobile device
Intern
Joined: 17 Jan 2020
Posts: 2
Own Kudos [?]: 0 [0]
Given Kudos: 33
Re: X takes 10 days to complete a task. Y takes half that time [#permalink]
what a tricky question/. phrasing :/
Intern
Joined: 18 Nov 2020
Posts: 4
Own Kudos [?]: 0 [0]
Given Kudos: 116
Location: Mexico
Concentration: Finance, General Management
GPA: 3.43
WE:Operations (Hospitality and Tourism)
Re: X takes 10 days to complete a task. Y takes half that time [#permalink]
I cannot make sense of the answer no matter how you put it. Could you further explain?

Considering the 100 units of work, if A has done 40 of them at a rate of 10 per day= 4 days.
Y came and he does does double, thus 20 units per day. If they are working together, they do 30 units per day. In 2 days they will do 60 units of work.

X works 4 alone. Y joins and together with X finish the job in 2 more days.

What am i missing here?

Thank you,
Manager
Joined: 07 Oct 2022
Posts: 93
Own Kudos [?]: 19 [0]
Given Kudos: 45
Location: Nigeria
Re: X takes 10 days to complete a task. Y takes half that time [#permalink]
Why is everyone solving for time it will take Y alone to complete 60% of work? The question said time taken for X and Y working together to complete the task. The answer should be 2 days not 3.

Posted from my mobile device
Director
Joined: 17 Dec 2012
Posts: 588
Own Kudos [?]: 1531 [0]
Given Kudos: 20
Location: India
Re: X takes 10 days to complete a task. Y takes half that time [#permalink]
Solution

Time actually worked by x = ax and by Y = ay
ax is also equal to ax1 + ax2 where ax1 is the time worked by x alone and ax2 time worked together and ax2=ay

ax/10+ay/5 = 1
(ax1/10 + ax2/10) +ay/5 =1
(ax1/10 +ay/10) +ay/5=1
ay/5 =1-4/10 = 6/10
ay=3
Non-Human User
Joined: 09 Sep 2013
Posts: 33151
Own Kudos [?]: 829 [0]
Given Kudos: 0
Re: X takes 10 days to complete a task. Y takes half that time [#permalink]
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Re: X takes 10 days to complete a task. Y takes half that time [#permalink]
1   2
Moderator:
Math Expert
93417 posts