Chethan92 wrote:
There are 25 primes between 1-100 and 46 primes between 1-200.
168 primes between 1 to 1000. This info is enough for GMAT
You'd never need to know any of these things to answer a real GMAT question. This question:
Chethan92 wrote:
If P is a set of integers from 2 to 100 (Inclusive) and Q is another set of integers from 101 to 200 (Inclusive). Then how many elements of Q are there such that Q doesn't have any elements of P as factors?
is miles out of scope for the GMAT. It also doesn't even make sense. It asks for elements of Q "such that
Q doesn't have any elements of P as factors". But "Q" is a set. It's not a number. I don't even know what the question could mean. I imagine the intended meaning is "how many elements of Q are not divisible by any element in P", but that's not what the question says. It also needs to say that P is *the* set of integers from 2 to 100 inclusive, not "a" set, because {2, 3, 100} is, for example, "a set" of integers from 2 to 100 inclusive. As written, we don't even know what the sets P and Q are, so we can't answer a question about them.
What is the source? There's no reason anyone preparing for the GMAT should look at this question.