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

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

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22 Oct 2015, 20:00
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15% (low)

Question Stats:

79% (01:12) correct 21% (01:46) wrong based on 144 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

48 Hour Window Answer & Explanation Window
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
[Reveal] Spoiler: OA

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# Rich Cohen

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Special Offer: Save $75 + GMAT Club Tests Free Official GMAT Exam Packs + 70 Pt. Improvement Guarantee www.empowergmat.com/ ***********************Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!*********************** Last edited by EMPOWERgmatRichC on 27 Oct 2015, 21:38, edited 1 time in total.  EMPOWERgmat Discount Codes Economist GMAT Tutor Discount Codes Optimus Prep Discount Codes Current Student Joined: 20 Mar 2014 Posts: 2689 Concentration: Finance, Strategy Schools: Kellogg '18 (M) GMAT 1: 750 Q49 V44 GPA: 3.7 WE: Engineering (Aerospace and Defense) Re: Random Pack 1, Question 2 An assembly line produces 40 cogs per hour [#permalink] ### Show Tags 23 Oct 2015, 04:46 1 This post received KUDOS 1 This post was BOOKMARKED 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 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 Random 4-Pack series Scroll Down For Official Explanation 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. EMPOWERgmat Instructor Status: GMAT Assassin/Co-Founder Affiliations: EMPOWERgmat Joined: 19 Dec 2014 Posts: 11312 Location: United States (CA) GMAT 1: 800 Q51 V49 GRE 1: 340 Q170 V170 Re: Random Pack 1, Question 2 An assembly line produces 40 cogs per hour [#permalink] ### Show Tags 25 Oct 2015, 13:35 1 This post received KUDOS Expert's post 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 Final Answer: [Reveal] Spoiler: C GMAT assassins aren't born, they're made, Rich _________________ 760+: Learn What GMAT Assassins Do to Score at the Highest Levels Contact Rich at: Rich.C@empowergmat.com # Rich Cohen Co-Founder & GMAT Assassin Special Offer: Save$75 + GMAT Club Tests Free
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Re: Random Pack 1, Question 2 An assembly line produces 40 cogs per hour [#permalink]

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29 Oct 2015, 09:54
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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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05 Nov 2015, 22:00
1
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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
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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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

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

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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
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
Re: Random Pack 1, Question 2 An assembly line produces 40 cogs per hour   [#permalink] 20 Mar 2017, 04:00
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