Last week I complained about a reference to “a straight ladder”, which I considered absurd because all ladders are straight.
So far three people have written to me to suggest that A-frame stepladders are not straight. I had considered these (I own one) but I did not consider them to be exceptions. The ladder part is straight; the rest of it is a support for the ladder.
But I think there is an argument to be made in the other direction also: “straight ladder” is sometimes used as a term of art for a ladder that is specifically not an A-frame stepladder, and we can imagine that the authors of the question meant it in this technical sense, even though the target audience is a bunch of middle-schoolers who would not be aware of this distinction. Particularly since the rest of the problem does not make sense if the “straight ladder” is interpreted as an A-frame. (It is about how far up the wall the ladder can reach if its bottom is placed at the maximum safe distance.)
Since I am on the topic anyway, I should mention that Google search for “curved ladders” did produce many indisputably curved ladders, all of them playground equipment. The middle-schoolers would certainly be familiar with these, so perhaps the authors of the question were right to add the qualification.
The best point, however, was raised by Leah Neukirchen, who observed that rope ladders need not be straight, or perhaps that they should not be considered straight even if they happen to be hanging straight at the moment. Without sarcasm, I say: I stand corrected.