Statements :1. Some soldiers are famous.
2. Some soldiers are intelligent.
Conclusions:1.Some soldiers are either famous or intelligent.
2.Some soldiers are neither famous nor intelligent.

see. In first two sentence, the no of soldiers who are famous, are not certain . we can say that - either some are not famous/intelligent or we can say all soldiers are famous/intelligent.

but in your 3rd and 4th sentence , All soldiers are famous/intelligent.

So, let the universe be the students in your class. (If the universe is not defined always consider the most general option). So, this means at least one student from class went to delhi. So, this implies:

$\exists x, G(x)$

and also

$\neg \forall x, \neg G(x)$ (which means it is not the case that no one had gone to Delhi)

Now,

Everyone went to Delhi.

This means every student in class went to Delhi which implies

$\neg \exists x, \neg G(x)$.

Now, the second case implies first. (This requires that the universe be non-empty, here it means at least one student in class and this assumption is usually used in many first order logic proofs)