tim Wrote:I think the GMAT would still consider this incorrect regardless of which preposition you use, because we still don't know who is doing the "using".
Yes, but in that case 'using' would not be required anymore. Example follows:
It is correct to say: The problem in the existing software was fixed with the new patch.
While saying, The problem in the existing software was fixed by the new patch. is not appropriate.
And saying , The problem in the existing software was fixed using new patch.
is incorrect as stated above, as we do not have an appropriate subject for using.
Experts, correct me if I am wrong. Thank you!