In this sentence is plan (singular or plural)?
Which is correct:
Neither Mary or Jim plan to go camping.
Neither Mary or Jim plans to go camping.
[CAUTION: I am not a teacher:take the advice and or corrections offered in this post at your own risk.
If you doubt the information, please get a qualified opinion from one of the teachers on these forums.]
Note that this seems to hold true as the two of them are referred to distinctly and separately, and note this structure:
Both Mary and Jim [both of them/they] plan to go camping.
Traditionally the second is correct, but many use the first nowadays too.