If two copying machines work simultaneously at their : GMAT Data Sufficiency (DS)
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# If two copying machines work simultaneously at their

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If two copying machines work simultaneously at their [#permalink]

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08 Sep 2009, 11:35
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If two copying machines work simultaneously at their respective constant rates, how many copies do they produce in 5 minutes?

(1) One of the machines produces copies at the constant rate of 250 copies per minute.
(2) One of the machines produces copies at twice the constant rate of the other machine.

OPEN DISCUSSION OF THIS QUESTION IS HERE: if-two-copying-machines-work-simultaneously-at-their-126653.html
[Reveal] Spoiler: OA
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Re: If two copying machines work simultaneously at their [#permalink]

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08 Sep 2009, 12:07
saruba wrote:
IMO C

even i marked the same answer, but the answer given is something else...
let us wait for few more response....
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Re: If two copying machines work simultaneously at their [#permalink]

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08 Sep 2009, 12:16
I think E is the answer

gurpreet07 wrote:
saruba wrote:
IMO C

even i marked the same answer, but the answer given is something else...
let us wait for few more response....
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Re: If two copying machines work simultaneously at their [#permalink]

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08 Sep 2009, 12:19
Ok I understand,
we don't know which machine is which, I mean, the machine that produces 250 could be the same which produces twice the other machine.
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12 Sep 2009, 20:52
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1, Insuf ->B,C,E
2, alone insuff -> C,E
1&2: 2 values - 1 machine 250, other 125
- 1 machine 250, other 500
-> E
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Re: If two copying machines work simultaneously at their [#permalink]

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12 Sep 2009, 23:09
Mikko wrote:
1, Insuf ->B,C,E
2, alone insuff -> C,E
1&2: 2 values - 1 machine 250, other 125
- 1 machine 250, other 500
-> E

Nice explantion....yes the OA is E
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Re: If two copying machines work simultaneously at their [#permalink]

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19 Sep 2009, 11:57
If two copying machines work simultaneously at their respective constant rates, how many copies do they produce in 5 minutes?
(1) One of the machines produces copies at the constant rate of 250 copies per minute.
(2) One of the machines produces copies at twice the constant rate of the other machine.

IMO E....let's say two machines A and B

1. A = 250/minute no relation between A and B => NS
2. A=2B or B=2A => NS

combining

we don't know A=250 or B=250 NS

Ans = > E

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Re: If two copying machines work simultaneously at their [#permalink]

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20 Sep 2009, 03:28
Statement 1 : insuff.

Statement 2: insuff,since the rate of other machine can be either 125 or 500.insuff

So I wud go with option E
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Re: If two copying machines work simultaneously at their [#permalink]

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03 Jan 2012, 10:48
Very critical question.
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Re: If two copying machines work simultaneously at their [#permalink]

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03 Jan 2012, 10:57
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Excellent question.
1. Clearly insufficient
2. No rate of one of the machines specified, so insufficient

Together, the two machines could be:
a. 250 cpm, 125 cpm
b. 250 cpm, 500 cpm
insufficient

So, E.
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Re: If two copying machines work simultaneously at their [#permalink]

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17 Mar 2015, 11:59
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Re: If two copying machines work simultaneously at their [#permalink]

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05 Apr 2015, 05:28
saruba wrote:
Ok I understand,
we don't know which machine is which, I mean, the machine that produces 250 could be the same which produces twice the other machine.

yeah, thought the same.WE can have 2 values from 2nd statement - 250+500 or 250 + 125
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Re: If two copying machines work simultaneously at their [#permalink]

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13 May 2016, 00:33
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Re: If two copying machines work simultaneously at their [#permalink]

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01 Aug 2016, 02:45
gurpreet07 wrote:
If two copying machines work simultaneously at their respective constant rates, how many copies do they produce in 5 minutes?

(1) One of the machines produces copies at the constant rate of 250 copies per minute.
(2) One of the machines produces copies at twice the constant rate of the other machine.

(1) One of the machines produces copies at the constant rate of 250 copies per minute.
We don't know the rate of other machine
INSUFFICIENT

(2) One of the machines produces copies at twice the constant rate of the other machine
The rate of the other machine can be 125 or 250
INSUFFICIENT

Merging both
one machine = 250; other machine 125 or 250

INSUFFICIENT

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Re: If two copying machines work simultaneously at their [#permalink]

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18 Sep 2016, 20:42
gurpreet07 wrote:
If two copying machines work simultaneously at their respective constant rates, how many copies do they produce in 5 minutes?

(1) One of the machines produces copies at the constant rate of 250 copies per minute.
(2) One of the machines produces copies at twice the constant rate of the other machine.

E

1) Don't know the rate of the other machine
2) (x+y)5=? x=2y, (3y)5=? still don't have rate for one of the machine
1+2) You don't know which of the two machine has rate of 250. if x=250, y=250/2. If y=250, x=500. Therefore, you can get two different outputs depending on where you define the rate of 250.
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Re: If two copying machines work simultaneously at their [#permalink]

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12 Nov 2016, 20:29
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I got the answer initially wrong as I was in a hurry to finish it under 17 sec LOL. This is where people like me get killed.
A=RT
Amount of work A =1
R=(1/R1+1/R2)
T= time required.

Statemeent 1: Ofcourse insufficient as only one rate is given
Statement 2: Insufficient as only a comparison relationship is given and no numeric values

Ans C is very tempting as basic human tendency of joining dots for our benefit but hey wait. it is said " One machine produces copies twice the other but we don't know which one is producing twice the other
M1=250 M2=500
or
M1=250 M2= 125??

Understood? There is noway a clear mention of M1<M2 OR m2<m1 and what is the value of either of M1 or M2.
So yeah the answer is E.

Hope this helps
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Re: If two copying machines work simultaneously at their [#permalink]

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13 Nov 2016, 05:45
[quote="gurpreet07"]If two copying machines work simultaneously at their respective constant rates, how many copies do they produce in 5 minutes?

(1) One of the machines produces copies at the constant rate of 250 copies per minute.
(2) One of the machines produces copies at twice the constant rate of the other machine.

/quote]

Straight E, though a little bit tricky. All we need to know is the rates of these machines. Though from both statement the rates can be:
250 copies per minute and 500 copies per minute;
250 copies per minute and 125 copies per minute.

OPEN DISCUSSION OF THIS QUESTION IS HERE: if-two-copying-machines-work-simultaneously-at-their-126653.html[
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Re: If two copying machines work simultaneously at their   [#permalink] 13 Nov 2016, 05:45
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