(I). A and E are good in studies; C is poor in studies. The remaining two i.e. B and D are average in studies.
(II). A comes from a rich family; E belong to a poor family.
Now, B and D are average in studies. So, B and D come from middle-class families.
Now, C remains. So, C belongs to a poor family (because two boys come from poor families).
(III). The students who are poor and average in studies are in under-graduate classes i.e. B, C and D.
The remaining two i.e. A and E study in post-graduate classes.
(IV). B, C and E are industrious. A is not industrious. Now, two boys are not industrious.
So, D is also not industrious.
(V). Two boys interested in acting are not industrious. So, A and D are interested in acting. The boy interested in music comes from middle-class family. B and D come from middle-class families. But D is interested in acting. So, B is interested in music. E is not interested in any activity. Clearly, C is interested in sports.
D is not industrious and is average in studies.