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On Thursday afternoon, two machines, J and R, ran continuously at unif

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On Thursday afternoon, two machines, J and R, ran continuously at unif [#permalink]

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On Thursday afternoon, two machines, J and R, ran continuously at uniform rates to fill a production order. How long did it take them to fill the order?

(1) Machine R produces 6 orders per hour.
(2) Machine J produces 4 orders per hour.
[Reveal] Spoiler: OA

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Re: On Thursday afternoon, two machines, J and R, ran continuously at unif [#permalink]

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New post 09 May 2017, 02:41
(1) Machine R produces 6 orders per hour.
Knowing just the number of orders Machine R is not enough to know how long it took both of them to fill the order.
Hence, insufficient.

(2) Machine J produces 4 orders per hour.
Knowing just the number of orders Machine J is not enough to know how long it took both of them to fill the order.
Hence, insufficient.

But combining the information we can clearly say how long it took the machines to fill the production order(Option C)
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On Thursday afternoon, two machines, J and R, ran continuously at unif [#permalink]

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New post 09 May 2017, 04:14
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The production rates of both the machines are specified but then, the question doesn't mention the order size which needs to be completed. So, I believe nothing can be said about the time taken as long as this data is missing. Hence, the correct answer should be Option E.

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Re: On Thursday afternoon, two machines, J and R, ran continuously at unif [#permalink]

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New post 09 May 2017, 04:18
pushpitkc wrote:
(1) Machine R produces 6 orders per hour.
Knowing just the number of orders Machine R is not enough to know how long it took both of them to fill the order.
Hence, insufficient.

(2) Machine J produces 4 orders per hour.
Knowing just the number of orders Machine J is not enough to know how long it took both of them to fill the order.
Hence, insufficient.

But combining the information we can clearly say how long it took the machines to fill the production order(Option C)



Could you please help me with how you concluded that both the sentences combined would give us the solution even when the order size itself is unknown?

Thank you. :)

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Re: On Thursday afternoon, two machines, J and R, ran continuously at unif [#permalink]

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New post 09 May 2017, 04:34
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The problem can be solved with the 2 machine work formula: A*B/A+B
1) Gives us only the information of the rate of one machine
2) Same applies to statement 2
Combined we can set up the formula J*R/J+R=6*4/6+4=2.4, which is not necessary as soon as you know you have a 2V2E here.
The two rates are sufficient to solve.

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Re: On Thursday afternoon, two machines, J and R, ran continuously at unif [#permalink]

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New post 09 May 2017, 10:27
stat1: no info abt J,,,not suff

stat2: no info abt R ,,not suff

no info about the order a production order can contain,, option E

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Re: On Thursday afternoon, two machines, J and R, ran continuously at unif [#permalink]

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New post 08 Jun 2017, 04:19
I think that a lot of people are getting this question wrong becuse they assume that "an order" means ONE ORDER.
In fact I would suggest to change it with "an order of a particular size" for example...

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Re: On Thursday afternoon, two machines, J and R, ran continuously at unif [#permalink]

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New post 18 Jun 2017, 19:50
Answer: E, because the question doesn't mention how many orders are to be completed, therefore insufficient aka E.

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Re: On Thursday afternoon, two machines, J and R, ran continuously at unif [#permalink]

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New post 23 Oct 2017, 09:45
MvArrow wrote:
I think that a lot of people are getting this question wrong becuse they assume that "an order" means ONE ORDER.
In fact I would suggest to change it with "an order of a particular size" for example...


I didnt quite understand it Can you explain it?

According to me


(R1+ R2)*t=1
Therefore t=1/(R1+R2)

by Combining 1 and 2
we get R1 and R2

Bunuel
Would appreciate your inputs too

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Re: On Thursday afternoon, two machines, J and R, ran continuously at unif [#permalink]

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New post 23 Oct 2017, 20:07
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I think that many people forgot that an important point: you have to know the size of "a production order" that two machines, J and R, ran continuously at uniform rates to fill. We have:

(1) Machine R produces 6 orders per hour.
(2) Machine J produces 4 orders per hour.

=> we only know that in 1 hour, 2 machine can produce 10 orders. But the question doesn't say anything about how many orders are there in "a production order" that 2 machine have to fill. This "production order" can contain 1, 2 or even 100 orders => hence we can't conclude anything about "How long did it take them to fill the order?".

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Re: On Thursday afternoon, two machines, J and R, ran continuously at unif   [#permalink] 23 Oct 2017, 20:07
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