I got a sentence correction question, and I am having a hard time trying to figure out what and why exactly the error lies in the "as both are quite unpleasant experiences" part of the following sentence.
You must avoid riding in a crowded bus / or travelling in a metro / during rush hour / as both are quite unpleasant experiences.
(it's one complete sentence; slashes indicate parts of the sentence)
The answer (error) is in the last part i.e. "as both are quite unpleasant experiences", but I don't know why.