Hi

I am not sure on when to use double, twice, increase or two times

Regards,
Roger

well, i'll start by pointing out the obvious: unlike the other 3 constructions you've mentioned, 'increase' can refer to an increase of any size. so, if you don't actually mean 'double', then you need to use a more general term, like 'increase'.

the gmat would almost certainly prefer 'twice' to 'two times', because 'twice' is nice - it's more concise.

'double' is most often found as a verb.

have you seen any problems that focus on this distinction?

Thanks Ron

I will post a sentence as soon as I come across one.

Hi Ron! I think I have. 11th Edition SC #4. I will not reproduce the problem here but is the split between "twice" and "double" not a split in that problem? i.e., can I narrow my answer choices based on this split alone?

Thanks so much in advance.

Can someone clarify this issue? double vs. twice?

Thank you very much for your help.

hmm.

if i were you, i would memorize this as an example of idiomatic usage: just memorize which constructions go with 'double' and which ones go with 'twice'. the ones appearing in correct answers are, of course, correct, but you can never be 100% sure about the ones appearing in incorrect answers. you could take the "if they don't say it's wrong then it must be ok" approach and be right in MOST cases, but the answer explanations aren't always, as my grandfather used to say, completely complete.

in any case, i'm quite sure that "double as many" or "double as much" would be wrong; you'd need "twice" in those cases.

hope that helps, and sorry there's no easy rule to throw at you.