let there are 100 students
if I say " there is one computer for every ten students" or "every ten students has/have one computer".
are these two statements same?
does it mean that there are ten computers for 100 students?
should it be has or have?

the former sentence,
there is one computer for every ten students
just presents a ratio: it says that the ratio of computers to students is 1 : 10. that's all it says.
in particular, it implies nothing about the distribution of the computers; it's possible that one of the 100 students might have eight of the computers to himself, while the unlucky ninety-nine are left to fight over the other two.

the latter sentence,
every ten students have one computer (note it's very clearly have, because 'ten students' is very clearly plural)
seems to imply an even distribution, involving literal groups of ten students, each of which has access to one computer.

maNY MANY THANX