Data Sufficiency

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.

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.