4) Machines X & Y can produce components at their respective rates. How many more hours does Y take than X to produce a certain number of components?
A) X & Y working together take 2/3 of the time taken by X.
B) Y working alone takes Twice the time taken by X.
GMAT Prep1 DS Question
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Hi,
Statement 1:
Let X take 30 hours to complete the job.
1/30 + 1/Y = 1/20
1/Y = 1/20 - 1/30
1/Y = 1/60
In this case, Y takes 60 hours to complete the job.
Thus, if Y takes twice the times that X takes, then working together, they will complete the work in 2/3rd of the time taken by X alone.
How many more hours does Y take than X (in absolute terms) ? cannot tell - insufficient
Statement 2: Just a restatement of what has been implied by statement 1 - insufficient.
Combining 1 & 2: Does not take us much further.
Guess, it is E.
Hope this helps. Thanks.
Statement 1:
Let X take 30 hours to complete the job.
1/30 + 1/Y = 1/20
1/Y = 1/20 - 1/30
1/Y = 1/60
In this case, Y takes 60 hours to complete the job.
Thus, if Y takes twice the times that X takes, then working together, they will complete the work in 2/3rd of the time taken by X alone.
How many more hours does Y take than X (in absolute terms) ? cannot tell - insufficient
Statement 2: Just a restatement of what has been implied by statement 1 - insufficient.
Combining 1 & 2: Does not take us much further.
Guess, it is E.
Hope this helps. Thanks.
Naveenan Ramachandran
4GMAT, Dadar(W) & Ghatkopar(W), Mumbai
4GMAT, Dadar(W) & Ghatkopar(W), Mumbai