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?
Answer Choices
Correct answer marked belowSee the full step-by-step explanation
You can see the correct answer above. Sign in for free to unlock the complete worked solution.
Track your performance and improve
Get detailed analytics, unlock full explanations, and move up difficulty tiers as you practice.
Unlock the full explanation
Create a free account to reveal the correct answer, see the step-by-step explanation, and start tracking your GMAT progress.
Got 24, but I did it the long way with y = 48. Anyone else pick a number?
Same, picking a value for y is definitely the move here.
Is the answer 24? I keep getting 12 because I divided by 2 somewhere instead of multiplying.
Check your setup — doubling the widgets while halving the time means you need 4× the machine-hours, so 4× the machines.
Wait, are we supposed to assume the rate is identical for all machines? The wording says 'identical constant rate' so I think yes.
Correct, identical rate means total machine-hours scale linearly. That's the key assumption.
Easy one for me. Just set up (6)(8) = y and (n)(4) = 2y, then divide. n = 24.
What it tests
Your ability to combine individual work rates, usually by working with the fraction of a job completed per unit of time.
Common trap
Adding the times instead of the rates, or forgetting to take the reciprocal when combining rates.