Usage of "in which" vs "where

[sana.noor]

Hi Ron, Stacey, tim and everyone!
can we use "comma + in which"? i was going through OG 2016 and found the following construction right. as per Manhattan prep rules i cant post the question. But i am writing the skeleton of the sentence to give an idea.
"Companies are using more and more network computers for such tasks as X, Y and Z, in which standard business tasks are handled via A rather than B." as per gmat this structure is right but i really dont understand that why Comma + in which referring to?
can we use "where" instead of "in which

[RonPurewal]

if you're looking at a correct answer, then 'what does ____ refer to?' is a question you should ALWAYS be able to answer by just using your everyday common sense.
i.e., in context there's almost certainly ONE (and only one) thing that would actually make sense as the referent of '___'. if the sentence is correct then it has to make sense, and thus you'll know exactly what '___' is meant to stand for.

[RonPurewal]

in any case, if you are still genuinely confused—even after using common sense to think about 'What is this sentence actually saying?'—then please give the problem number of the OG item that you have in mind. thanks.

[sana.noor]

Respected Ron!
its question # 80 from OG 2016

[RonPurewal]

in context, it's clear that 'which' = 'electronic data interchange'. (it certainly doesn't describe the entire list.)

what's MUCH more important, though, is that there's no need to go into such detail.
there are only two options:
• 'in which'
• 'where'

it should be quite clear that 'where' is incorrect (we're not talking about a location)... so, done.