Sentence Correction

Hi All,

Somewhere I read that we should use "majority" with countable nouns only. e.g. dollars, hats etc.

E.g. Correct:
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Majority of the students went to the picnic.
(Here students is countable)

Incorrect
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Majority of the talk was devoted to history.
(Here talk is uncountable)

But Manhattan SC guide does not talk anything like this. Infact Manhtattan SC guide give example of usage of Majority with both countable and uncountable nouns.

Examples from Manhattan SC guide
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a) The majority of the students in this class are hard workers
b) In the Senate, the majority Has coalesced into a unified voting block.

I am really confused. Can someone please tell what indeed is the case ?

Thanks
Mohit