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Random Pack 1, Question 2 An assembly line produces 40 cogs per hour

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Random Pack 1, Question 2 An assembly line produces 40 cogs per hour  [#permalink]

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New post Updated on: 27 Oct 2015, 21:38
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Question Stats:

80% (01:37) correct 20% (01:41) wrong based on 152 sessions

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QUANT 4-PACK SERIES Problem Solving Pack 1 Question 2 At a company meeting...

An assembly line produces 40 cogs per hour until an initial order of 60 cogs is completed. The speed of the assembly line is then immediately increased so that it can produce 60 cogs per hour until another 60 cogs are produced. What is the average output, in cogs per hour, for the assembly line during this time?

A) 42
B) 45
C) 48
D) 50
E) 55

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OA, and explanation will be posted after the 48 hour window closes.

This question is part of the Quant 4-Pack series

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Originally posted by EMPOWERgmatRichC on 22 Oct 2015, 20:00.
Last edited by EMPOWERgmatRichC on 27 Oct 2015, 21:38, edited 1 time in total.
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Re: Random Pack 1, Question 2 An assembly line produces 40 cogs per hour  [#permalink]

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New post 23 Oct 2015, 04:46
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EMPOWERgmatRichC wrote:
RANDOM 4-PACK SERIES Pack 1 Question 2 At a company meeting...

An assembly line produces 40 cogs per hour until an initial order of 60 cogs is completed. The speed of the assembly line is then immediately increased so that it can produce 60 cogs per hour until another 60 cogs are produced. What is the average output, in cogs per hour, for the assembly line during this time?

A) 42
B) 45
C) 48
D) 50
E) 55

48 Hour Window Answer & Explanation Window
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OA, and explanation will be posted after the 48 hour window closes.

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Initial conditions:

40 cogs/h for 60 cogs --> total time to produce 60 cogs = 60/40 = 1.5 hours.

After ramping up the production, 60 cogs/ hour for 60 cogs ---> 1 hour more.

Total time = 1.5+1 = 2.5 hours, producing 60+60 = 120 cogs,

Thus the average output = 120/2.5 = 48 cogs/hour. C is the correct answer.
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Re: Random Pack 1, Question 2 An assembly line produces 40 cogs per hour  [#permalink]

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New post 25 Oct 2015, 13:35
1
Hi All,

This question revolves around rates and average overall rates, so it can be treated the same way that you would treat an Average Speed question. To determine the average output per hour, we need to know the total cogs produced and the total time spent producing those cogs.

For the first part of the order, we know the rate (40 cogs/hour) and the total produced (60 cogs), so we can figure out the amount of time...

Total Cogs = (Production Rate)(Time)
60 cogs = (40 cogs/hr)(T hours)
60/40 = T
1.5 hours = T

For the second part of the order, we have the same types of information to work with (60 cogs/hr and 60 cogs produced)....

Total Cogs = (Production Rate)(Time)
60 cogs = (60 cogs/hr)(T hours)
60/60 = T
1 hour = T

With the TOTAL COGS (60 + 60 = 120 cogs) and the TOTAL TIME (1.5 + 1 = 2.5 hours), we can now calculate the AVERAGE production rate, in cogs per hour, for the assembly line:

Total Cogs = (Production Rate)(Total Time)
120 cogs = (Rate)(2.5 hours)
120/2.5 = Rate
48 cogs/hour = R

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Re: Random Pack 1, Question 2 An assembly line produces 40 cogs per hour  [#permalink]

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New post 29 Oct 2015, 09:54
1
First rate = 40cogs/hr till 60 cogs are produced
So n1=60, t1=60/40=1.5 hrs

Second rate = 60 cogs/hr till another 60 cogs are produced.
So n2=60, t2=60/60=1 hr.

In total the average no. of cogs produced per hour =\(\frac{total no. of cogs}{Total no. of hours}\)
=\(\frac{120}{2.5}\)
=48 cogs/hr
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Re: Random Pack 1, Question 2 An assembly line produces 40 cogs per hour  [#permalink]

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New post 05 Nov 2015, 22:00
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EMPOWERgmatRichC wrote:
QUANT 4-PACK SERIES Problem Solving Pack 1 Question 2 At a company meeting...

An assembly line produces 40 cogs per hour until an initial order of 60 cogs is completed. The speed of the assembly line is then immediately increased so that it can produce 60 cogs per hour until another 60 cogs are produced. What is the average output, in cogs per hour, for the assembly line during this time?

A) 42
B) 45
C) 48
D) 50
E) 55

48 Hour Window Answer & Explanation Window
Earn KUDOS! Post your answer and explanation.
OA, and explanation will be posted after the 48 hour window closes.

This question is part of the Quant 4-Pack series

Scroll Down For Official Explanation


As soon as you realize its testing the Rates/Distance basics, it becomes quite trivial.
Just translate in terms of Speed and Distance:
Speed1 : 40 cogs/hr
Distance1: 60 Cogs

Spped2: 60 cogs/hr
Distance2: 60 cogs


Avg speed (when distances are same) : \(\frac{2*S1*S2}{S1+S2}\)
\(=> \frac{2*40*60}{40+60}\)
\(=> 48 cogs/hr\)

Option C

Please let me know if im wrong.
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Re: Random Pack 1, Question 2 An assembly line produces 40 cogs per hour  [#permalink]

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New post 06 Nov 2015, 12:30
EMPOWERgmatRichC wrote:
An assembly line produces 40 cogs per hour until an initial order of 60 cogs is completed.


Hour 1 = 40 cogs
Hour 1\(\frac{1}{2}\) = 60 cogs

EMPOWERgmatRichC wrote:
The speed of the assembly line is then immediately increased so that it can produce 60 cogs per hour until another 60 cogs are produced


Hour 2\(\frac{1}{2}\) = 60 cogs

Hence after 2\(\frac{1}{2}\) from starting 120 cogs are produced.

EMPOWERgmatRichC wrote:
What is the average output, in cogs per hour, for the assembly line during this time?


Average cogs produced per Hour = Total No of cogs produced/Time from starting production

Average cogs produced per Hour = 120/2\(\frac{1}{2}\) => 48 cogs per hour.

A) 42
B) 45
C) 48
D) 50
E) 55

Hence answer is (C)

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Re: Random Pack 1, Question 2 An assembly line produces 40 cogs per hour  [#permalink]

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New post 20 Mar 2017, 04:00
EMPOWERgmatRichC wrote:
QUANT 4-PACK SERIES Problem Solving Pack 1 Question 2 At a company meeting...

An assembly line produces 40 cogs per hour until an initial order of 60 cogs is completed. The speed of the assembly line is then immediately increased so that it can produce 60 cogs per hour until another 60 cogs are produced. What is the average output, in cogs per hour, for the assembly line during this time?

A) 42
B) 45
C) 48
D) 50
E) 55

48 Hour Window Answer & Explanation Window
Earn KUDOS! Post your answer and explanation.
OA, and explanation will be posted after the 48 hour window closes.

This question is part of the Quant 4-Pack series

Scroll Down For Official Explanation


with 40 cogs/hr, to produce 60 cogs, time taken is 60/40 = 1.5 hrs
with 60 cogs/hr, to produce 60 cogs, time taken is 60/60 = 1 hrs

Total time taken is 1.5 +1 = 2.5
total cogs produced = 120

average rate = 120/2.5 =48 cogs/hr
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Re: Random Pack 1, Question 2 An assembly line produces 40 cogs per hour &nbs [#permalink] 20 Mar 2017, 04:00
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