sir did not understand can you say with an example

sir does it means it is the cut off for specific branches

Suppose there is a college A, which takes 50 students, now there is an exam where 100 sttudetns take part, out of those, there are 40 students who have say 70 marks out of 100, 10 students have marks from 90 out of 100 and the remaining 50 students have marks less than 70, say all of them have 40 marks out of 100. Now the cutoff will be 70, as there are exactly 50 seats in the college, and there are exactly 50 students with marks equal to or greater than 70. The intake will be 50.