It is currently 22 Nov 2017, 23:10

### 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 June
Open Detailed Calendar

# 3 machines have a productivity ratio of 1 to 2 to 5. All 3

Author Message
TAGS:

### Hide Tags

Manager
Joined: 10 Nov 2010
Posts: 246

Kudos [?]: 412 [2], given: 22

Location: India
Concentration: Strategy, Operations
GMAT 1: 520 Q42 V19
GMAT 2: 540 Q44 V21
WE: Information Technology (Computer Software)
3 machines have a productivity ratio of 1 to 2 to 5. All 3 [#permalink]

### Show Tags

16 Feb 2011, 04:34
2
KUDOS
19
This post was
BOOKMARKED
00:00

Difficulty:

55% (hard)

Question Stats:

67% (01:54) correct 33% (02:53) wrong based on 222 sessions

### HideShow timer Statistics

3 machines have a productivity ratio of 1 to 2 to 5. All 3 machines are working on a job for 3 hours. At the beginning of the 4th hour, the slowest machine breaks. It is fixed at the beginning of hour seven, and begins working again. The job is done in nine hours. What was the ratio of the work performed by the fastest machine as compared to the slowest?

A. 5
B 7
C 15/2
D 17/2
E 12
[Reveal] Spoiler: OA

_________________

The proof of understanding is the ability to explain it.

Kudos [?]: 412 [2], given: 22

Math Expert
Joined: 02 Sep 2009
Posts: 42305

Kudos [?]: 133080 [7], given: 12403

Re: 3 machines have a productivity ratio of 1 to 2 to 5. All 3 [#permalink]

### Show Tags

16 Feb 2011, 07:50
7
KUDOS
Expert's post
9
This post was
BOOKMARKED
3 machines have a productivity ratio of 1:2:5. all 3 machines are working on a job for 3 hours. at the beginning of the 4th hour, the slowest machine breaks. it is fixed at the beginning at hour 7, and begins working again. the job is done in 9 hours. what was the ratio of the work performed by the fastest machine to the work performed by the slowest?

"3 machines have a productivity ratio of 1:2:5" means that in a time interval (1 hour, 1 year, ...) the first machine can produce 1 part (so it's the slowest one), the second can produce 2 parts and the third and fastest one can produce 5 parts.

Now, the fastest machine worked for whole 9 hours thus produced 9*5=45 parts but the slowest machine worked only for 6 hours thus produced 6*1=6 parts, so the ratio of the work performed by the fastest machine to the work performed by the slowest is 45/6=15/2.
_________________

Kudos [?]: 133080 [7], given: 12403

Math Forum Moderator
Joined: 20 Dec 2010
Posts: 1965

Kudos [?]: 2098 [1], given: 376

Re: 3 machines have a productivity ratio of 1 to 2 to 5. All 3 [#permalink]

### Show Tags

16 Feb 2011, 04:49
1
KUDOS
3
This post was
BOOKMARKED
1:2:5

Let's consider 1 work is done by the slowest machine in 1 hour.

in first 3 hours; Work performed by 3 machines
1*3:2*3:5*3

From beginning of 4th hour until start of 7th hour, 3 hours elapsed. Work performed by 3 machines
0:2*3:5*3. First one is 0 work as it is broken.

Job is done in nine hours; from start of 7th hour until end of 9th hour, 3 hours elapsed. Work performed by 3 machines
1*3:2*3:5*3

Total work performed by slowest machine: 3+3=6
Total work performed by fastest machine: 15+15+15=45

Ratio = 45/6 = 15/2

Ans: 15/2
_________________

Kudos [?]: 2098 [1], given: 376

Senior Manager
Joined: 08 Nov 2010
Posts: 392

Kudos [?]: 129 [1], given: 161

Re: 3 machines have a productivity ratio of 1 to 2 to 5. All 3 [#permalink]

### Show Tags

11 Aug 2011, 06:02
1
KUDOS
ruturaj wrote:
please explain how slowest machine works for 6 hours

slowest machine worked
1st hour
2nd hour
3rd hour
Got broken
got fixed and returned to work at the beginning of the 7th hour so:
7th hour
8th hour
9th hour

Total of 6 hours.

So the slowest machine made 6 pieces, while the fastest machine made 45
_________________

Kudos [?]: 129 [1], given: 161

Senior Manager
Status: mba here i come!
Joined: 07 Aug 2011
Posts: 261

Kudos [?]: 1248 [1], given: 48

Re: 3 machines have a productivity ratio of 1 to 2 to 5. All 3 [#permalink]

### Show Tags

21 Aug 2011, 10:37
1
KUDOS
let's suppose that in 1 hour each machine produces 1+2+5 = 8 units

in 3 hrs = 24 units
next 3 hrs = 21 units (slowest isnt working)
further 3 hrs = 24 untis

fastest worked for 9 hours, while the slowest worked for 6 hrs.

units produced by fastest / units produced by slowest = 9*5/6*1 = 15/2
_________________

press +1 Kudos to appreciate posts

Kudos [?]: 1248 [1], given: 48

Director
Joined: 07 Dec 2014
Posts: 839

Kudos [?]: 272 [1], given: 15

Re: 3 machines have a productivity ratio of 1 to 2 to 5. All 3 [#permalink]

### Show Tags

05 Jan 2017, 17:19
1
KUDOS
GMATD11 wrote:
3 machines have a productivity ratio of 1 to 2 to 5. All 3 machines are working on a job for 3 hours. At the beginning of the 4th hour, the slowest machine breaks. It is fixed at the beginning of hour seven, and begins working again. The job is done in nine hours. What was the ratio of the work performed by the fastest machine as compared to the slowest?

A. 5
B 7
C 15/2
D 17/2
E 12

fastest machine's work=9hrs*5 units per hr=45 total units
slowest machine's work=6 hrs*1 unit per hr=6 total units
45/6=15/2

Kudos [?]: 272 [1], given: 15

Senior Manager
Joined: 08 Nov 2010
Posts: 392

Kudos [?]: 129 [0], given: 161

Re: 3 machines have a productivity ratio of 1 to 2 to 5. All 3 [#permalink]

### Show Tags

17 Feb 2011, 12:45
thanks for posting +1
_________________

Kudos [?]: 129 [0], given: 161

Manager
Joined: 07 Dec 2010
Posts: 111

Kudos [?]: 41 [0], given: 12

Concentration: Marketing, General Management
Re: 3 machines have a productivity ratio of 1 to 2 to 5. All 3 [#permalink]

### Show Tags

11 Aug 2011, 05:27
please explain how slowest machine works for 6 hours

Kudos [?]: 41 [0], given: 12

Math Forum Moderator
Joined: 20 Dec 2010
Posts: 1965

Kudos [?]: 2098 [0], given: 376

Re: 3 machines have a productivity ratio of 1 to 2 to 5. All 3 [#permalink]

### Show Tags

11 Aug 2011, 08:02
ruturaj wrote:
please explain how slowest machine works for 6 hours

3 machines have a productivity ratio of 1:2:5. all 3 machines are working on a job for 3 hours. at the beginning of the 4th hour, the slowest machine breaks. it is fixed at the beginning at hour 7, and begins working again. the job is done in 9 hours. what was the ratio of the work performed by the fastest machine to the work performed by the slowest?

Productivity ratio of 1:2:5 means;

In 1 hour:
Slowest machine just finishes 1 work
Medium fast machine finishes 2 work
Fastest machine finishes 5 work

3 hours work:
Slowest: 3*1=3 work
Medium: 3*2=6 work
Fastest: 3*5=15 work

THEN SLOWEST BREAKS.
It misses(3 hours):
4th hour
5th hour
6th hour

During which:
Medium fast completes: 3*2=6 work
Fastest completes: 3*5=15 work

Then
7th, 8th, 9th hour(3 hours)
Slowest: 3*1=3 work
Medium: 3*2=6 work
Fastest: 3*5=15 work

Work by fastest:Work by slowest
15+15+15:3+3
45:6
15:2
_________________

Kudos [?]: 2098 [0], given: 376

VP
Status: There is always something new !!
Affiliations: PMI,QAI Global,eXampleCG
Joined: 08 May 2009
Posts: 1283

Kudos [?]: 286 [0], given: 10

Re: 3 machines have a productivity ratio of 1 to 2 to 5. All 3 [#permalink]

### Show Tags

12 Aug 2011, 00:22
0-1 fastest = 5 slowest = 1
1-2----5----------1 ----
2-3 fastest = 5 ----1---

6-7----5--------1--
7-8----5---------1--
8-9----5---------1--

hence total = 45 and 6

thus 15/2
_________________

Visit -- http://www.sustainable-sphere.com/
Promote Green Business,Sustainable Living and Green Earth !!

Kudos [?]: 286 [0], given: 10

Director
Joined: 01 Feb 2011
Posts: 725

Kudos [?]: 147 [0], given: 42

Re: 3 machines have a productivity ratio of 1 to 2 to 5. All 3 [#permalink]

### Show Tags

21 Aug 2011, 14:29
Let M1 be the slowest and M3 be the fastest machine.

<---first 3 hours--><----3 hours----><---3 hours---->

M1 M1
M2 M2 M2
M3 M3 M3

productivity ratio = 1:2:5 (which is per hour)

x: 2x: 5x

work done by M3/ work done by M1 = (9*5x) / (6*x) = 45/6 = 15/2

Kudos [?]: 147 [0], given: 42

Senior Manager
Joined: 13 Aug 2012
Posts: 458

Kudos [?]: 558 [0], given: 11

Concentration: Marketing, Finance
GPA: 3.23
Re: 3 machines have a productivity ratio of 1 to 2 to 5. All 3 [#permalink]

### Show Tags

02 Dec 2012, 22:49
The productivity ratio of the fastest machine to the slowest machine is 5:1.

The fastest machine worked for 9 straight hours. Thus, W = 5 x 9 = 45
The slowest machine brokedown in the 4th hour and was revived on the 7th hour. Thus, W = 1 x 6 = 6

The Output Ratio of fastest to slowest is 45 is to 6 ==> 15 : 2
_________________

Impossible is nothing to God.

Kudos [?]: 558 [0], given: 11

GMAT Tutor
Joined: 01 Oct 2016
Posts: 7

Kudos [?]: 3 [0], given: 0

Re: 3 machines have a productivity ratio of 1 to 2 to 5. All 3 [#permalink]

### Show Tags

05 Jan 2017, 15:19
Let's say the productivity ratio refers to how many units each produces in 1 hour. The fastest (most productive) machine works for 9 hours and makes 5 per hour, totally 45 units. The slowest (least productive) machine works for 6 hours and produces 1 per hour for a total of 6. Thus, the ratio of units produced fast/slow is 45/6 or 15/2. No more math required
_________________

Dan the GMAT Man
Offering tutoring and admissions consulting in the NYC area and online
danthegmatman.squarespace.com
danthegmatman@gmail.com

Kudos [?]: 3 [0], given: 0

Intern
Joined: 08 May 2011
Posts: 21

Kudos [?]: 3 [0], given: 22

3 machines have a productivity ratio of 1 to 2 to 5. All 3 [#permalink]

### Show Tags

09 Apr 2017, 14:25
Common sense solution:

Ratio of work is 1:2:5

Meaning: As Bunuel defined "in a time interval (1 hour, 1 year, ...) the first machine can produce 1 part (so it's the slowest one), the second can produce 2 parts and the third and fastest one can produce 5 parts."

Time progression:

Hour 1: 1:2:5 parts produced
Hour 2: 2:4:10 parts produced
Hour 3: 3:6:15 parts produced
Hour 4: 3:8:20 parts produced //Machine 1 breaks, produces no more parts
Hour 5: 3:10:25 parts produced
Hour 6: 3:12:30 parts produced
Hour 7: 4:14:35 parts produced //Machine 1 is fixed, continues to produce parts
Hour 8: 5:16:40 parts produced
Hour 9: 6:18:45 parts produced //Job done

So when looking at the final tally of parts produced in 9 hours, the fastest machine produced 45 parts and the slowest produced only 6. Reducing this ratio we get 15/2.

Kudos [?]: 3 [0], given: 22

Intern
Joined: 15 Jun 2013
Posts: 45

Kudos [?]: 8 [0], given: 33

GMAT 1: 690 Q49 V35
GPA: 3.82
WE: Management Consulting (Manufacturing)
Re: 3 machines have a productivity ratio of 1 to 2 to 5. All 3 [#permalink]

### Show Tags

12 Apr 2017, 09:55
The productivity ratios are 1:2:5. Let's assume that the basic rate is x. So rates are 1x:2x:5x.
The fastes machine worked 9 hours, therefore it did 9/1x work. The slowest machine didn't work from 4th to 6th hours so were broken for 3 hours. Therefore the work done by this machine is 6/5x.
Let's compare work done by both machines: (9/1x)/(6/5x)=(9/x)*(5x/6)=15/2

Kudos [?]: 8 [0], given: 33

Re: 3 machines have a productivity ratio of 1 to 2 to 5. All 3   [#permalink] 12 Apr 2017, 09:55
Display posts from previous: Sort by