Last visit was: 21 Jul 2024, 01:24 It is currently 21 Jul 2024, 01:24
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.

# AcmeCorp claims that its new robotic vacuum, RoboVac, will remove 4/5

SORT BY:
Tags:
Show Tags
Hide Tags
Math Expert
Joined: 02 Sep 2009
Posts: 94433
Own Kudos [?]: 642638 [18]
Given Kudos: 86715
Board of Directors
Joined: 11 Jun 2011
Status:QA & VA Forum Moderator
Posts: 6049
Own Kudos [?]: 4767 [5]
Given Kudos: 463
Location: India
GPA: 3.5
Target Test Prep Representative
Joined: 14 Oct 2015
Status:Founder & CEO
Affiliations: Target Test Prep
Posts: 19175
Own Kudos [?]: 22685 [5]
Given Kudos: 286
Location: United States (CA)
General Discussion
Intern
Joined: 07 Nov 2016
Posts: 6
Own Kudos [?]: 3 [0]
Given Kudos: 33
Location: India
GMAT 1: 620 Q47 V29
GPA: 3.9
Re: AcmeCorp claims that its new robotic vacuum, RoboVac, will remove 4/5 [#permalink]
what is the answer for this.
I get it we have to find 4/5 of the dust left over after every consecutive run.
1st run-> 4/5
2nd run->4/5(1-4/5)
3rd run->4/5(4/5(1-4/5))
so the final answer should be = > 1st run + 2nd run+ 3rd run
It should be 124/125
VP
Joined: 09 Mar 2016
Posts: 1142
Own Kudos [?]: 1027 [0]
Given Kudos: 3851
Re: AcmeCorp claims that its new robotic vacuum, RoboVac, will remove 4/5 [#permalink]
divyamurali wrote:
what is the answer for this.
I get it we have to find 4/5 of the dust left over after every consecutive run.
1st run-> 4/5
2nd run->4/5(1-4/5)
3rd run->4/5(4/5(1-4/5))
so the final answer should be = > 1st run + 2nd run+ 3rd run
It should be 124/125

ARE YOU SURE OF YOUR ANSWER? IT SAYS "what fraction of the dust in her home will be removed?" I GOT 64/125
Intern
Joined: 15 Feb 2017
Posts: 1
Own Kudos [?]: 0 [0]
Given Kudos: 0
Re: AcmeCorp claims that its new robotic vacuum, RoboVac, will remove 4/5 [#permalink]
If we take 100 as an example:

(100/5)*4= 80
(80/5)*4= 64
(64/5*4)=51.2

So after 3 cycles: 51.2/100= 0.512
There is no such answer like that but if you divide 64/125 you get 0.512

Therefore answer A is the correct one.
Intern
Joined: 14 Sep 2016
Posts: 49
Own Kudos [?]: 37 [0]
Given Kudos: 119
Concentration: Finance, Economics
Re: AcmeCorp claims that its new robotic vacuum, RoboVac, will remove 4/5 [#permalink]
Bunuel wrote:
AcmeCorp claims that its new robotic vacuum, RoboVac, will remove 4/5 of the dust in a home or apartment in every cycle it runs. If Shay runs her new RoboVac three cycles in a row, what fraction of the dust in her home will be removed?

A. 64/125
B. 4/5
C. 21/25
D. 24/25
E. 124/125

Each time 1/5 dust will remain or a 5th of a 5th of a 5th.

This is the same as 5^-3.

$$\frac{1}{125}$$ will remain, $$\frac{124}{125}$$ removed.
GMAT Club Legend
Joined: 08 Jul 2010
Status:GMAT/GRE Tutor l Admission Consultant l On-Demand Course creator
Posts: 6020
Own Kudos [?]: 13812 [3]
Given Kudos: 125
Location: India
GMAT: QUANT+DI EXPERT
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
WE:Education (Education)
Re: AcmeCorp claims that its new robotic vacuum, RoboVac, will remove 4/5 [#permalink]
2
Kudos
1
Bookmarks
Bunuel wrote:
AcmeCorp claims that its new robotic vacuum, RoboVac, will remove 4/5 of the dust in a home or apartment in every cycle it runs. If Shay runs her new RoboVac three cycles in a row, what fraction of the dust in her home will be removed?

A. 64/125
B. 4/5
C. 21/25
D. 24/25
E. 124/125

First cycle Removes 4/5 dust so remaining dust after 1 cycle = 1-4/5 = 1/5

Second cycle Removes 4/5 of remaining dust so remaining dust after 2 cycles = (1/5)*(1/5) = 1/25

Third cycle Removes 4/5 of remaining dust so remaining dust after 3 cycles = (1/5)*(1/25) = 1/125

Hence, Dust removed = 1-1/125 = 124/125

Non-Human User
Joined: 09 Sep 2013
Posts: 34043
Own Kudos [?]: 853 [0]
Given Kudos: 0
Re: AcmeCorp claims that its new robotic vacuum, RoboVac, will remove 4/5 [#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: AcmeCorp claims that its new robotic vacuum, RoboVac, will remove 4/5 [#permalink]
Moderator:
Math Expert
94433 posts