Working simultaneously at an identical constant rate, it takes 6 machines 8 hours to produce y widgets. How many machines, working at that identical constant rate, are necessary to produce 2y widgets in 4 hours?
A. 6
B. 12
C. 18
D. 24
E. 48
The OA is D .
I am confused here. Can any experts clarify this PS question to me?
Working simultaneously at an identical constant rate,
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Hi VJesus12,
We're told that - working simultaneously at an identical constant rate - it takes 6 machines 8 hours to produce Y widgets. We're asked for the number of machines, working at that identical constant rate, are necessary to produce 2Y widgets in 4 hours.
With these types of Work questions, it helps to determine the total amount of work needed to complete a task.
(6 machines)(8 hours each) = 48 machine-hours of work to produce Y widgets.
The question asks us to create 2Y widgets, which is DOUBLE the number of widgets (above). Thus, it would take DOUBLE the work (re: 96 machine-hours of work). With just 4 hours to total time, we would need....
(X machines)(4 hours each) = 96 machine-hours of work to produce 2Y widgets.
X = 24 machines
Final Answer: D
GMAT assassins aren't born, they're made,
Rich
We're told that - working simultaneously at an identical constant rate - it takes 6 machines 8 hours to produce Y widgets. We're asked for the number of machines, working at that identical constant rate, are necessary to produce 2Y widgets in 4 hours.
With these types of Work questions, it helps to determine the total amount of work needed to complete a task.
(6 machines)(8 hours each) = 48 machine-hours of work to produce Y widgets.
The question asks us to create 2Y widgets, which is DOUBLE the number of widgets (above). Thus, it would take DOUBLE the work (re: 96 machine-hours of work). With just 4 hours to total time, we would need....
(X machines)(4 hours each) = 96 machine-hours of work to produce 2Y widgets.
X = 24 machines
Final Answer: D
GMAT assassins aren't born, they're made,
Rich
GMAT/MBA Expert
- Jeff@TargetTestPrep
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VJesus12 wrote:Working simultaneously at an identical constant rate, it takes 6 machines 8 hours to produce y widgets. How many machines, working at that identical constant rate, are necessary to produce 2y widgets in 4 hours?
A. 6
B. 12
C. 18
D. 24
E. 48
We are given that the rate of 6 machines is y/8. Using a proportion, we can determine how many machines work at a rate of 2y/4 = y/2.
6/(y/8) = n/(y/2)
48/y = 2n/y
48y = 2ny
24 = n
Alternate solution:
We see that the number of widgets needed to be produced (2y) is twice the given number of widgets (y). Thus, we need to double 6 machines to 12 machines so that in 8 hours they can produce 2y widgets. However, we see we need to produce these 2y widgets in 4 hours, which is half of the given 8 hours. Thus, we need to double the machines again from 12 machines to 24 machines to produce 2y widgets in 4 hours.
Answer: D
Jeffrey Miller
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