Are these two sentences correct according to English grammar?
Which story was longer?
Which story was the longest?
One of my colleagues said that the first question is wrong according to English.
Are these two sentences correct according to English grammar?
Which story was longer?
Which story was the longest?
One of my colleagues said that the first question is wrong according to English.
If you are talking about more than two stories, your colleague, I think, is right. You should use the superlative longest for more than two stories as follows:
Which story was the longest?
However, if you are talking about comparison between two stories, your colleague isn't right. You can use either the comparative longer or the superlative longest. So both the following sentences are correct:
Which story is (the) longer?
Which story is the longest?
You usually use the superlative with "the". But sometimes you use it without " the".
Besides, the use of the superlative for two things or persons is more common in informal English.