Can you guys help explain when to use "in which" and "whereby" on gmat sentence correction...i'm stumped.

i'm not sure exactly what you're asking about these things: do you want to know
1) what they mean?
2) acceptable placement? (ex: 'in which' has the same restrictions as plain 'which' - it must modify the noun that immediately precedes the comma)
3) acceptable antecedents?

please ask a specific question(s). thanks.

[content deleted]

you can't quote directly from the official guides. if you want to quote from problems, you should first make up your own sentences that use the same structures, and post those instead.

i'll still answer the question.

-- ron

whereby is used in the same way as prepositional constructions such as in which or to whom.

as with those constructions, you can't use whereby unless you follow it with an independent clause, AND the surrounding text (if you remove whereby + following text) is also an independent clause.

examples:
the new method, whereby the age of an artifact can be ascertained to within fifty years, will revolutionize the study of ancient history.
notice the following:
* the age of an artifact can be ascertained to within fifty years, by itself, is an independent clause
* the new method will revolutionize the study of ancient history (the remaining part of the sentence) is also an independent clause

that's the deal.