Question

[Robert_Chang]

Which is right?

Does each student need to work hard?

Do each student need to work hard?

[JMB1122]

Does each student need to work hard?

[shuja87]

Which is right?

Does each student need to work hard?

Do each student need to work hard?

For most singular subjects the simple present form of the verb is used. For exmaple:
The man plays football.
He dances very well.
The table shrieks.

In your example 'each student' can be thought of as a singular subject; therefore, we use 'needs'--the simple present form--instead of 'need.' So the correct sentence would be: Each student needs to work hard.

The same conventions are followed with none, one, etc.

None of them is a guitarist.
One of the students is a good singer.

[MikeNewYork]

For most singular subjects the simple present form of the verb is used. For exmaple:
The man plays football.
He dances very well.
The table shrieks.

In your example 'each student' can be thought of as a singular subject; therefore, we use 'needs'--the simple present form--instead of 'need.' So the correct sentence would be: Each student needs to work hard.

The same conventions are followed with none, one, etc.

None of them is a guitarist.
One of the students is a good singer.

Your post is correct, but it ignores the do/does part of the question. We don't use the inflected verb form with do/does. So the correct question is "Does each student need to study hard?" (does is singular)