A question from Sentence Correction (GMAT Verbal section) requires you to choose between 'did not know if the problem could be resolved' and 'did not know whether the problem could be resolved”.
Which one do you choose?
a. both could be correct
b. only "if" is correct
c. only "whether" is correct
Answer: c
Explanation: In GMAT, use 'if' only in conditional sentences. uses 'whatever' in all other cases.
