What comes next: 10, 20, 35, 55, ?

MANGO is written as PCQKR. How is APPLE written?

What comes next: A, C, F, J, O, ?

What comes next: 1, 8, 27, 64, ?

In a family of 8 members, A and B are married couple. A is male. C is the son of D, who is the brother of E. E is the daughter of F, who is the mother of G. G is the sister of A. How is C related to B?

Statements: All men are mortal. Socrates is a man. Conclusions: I. Socrates is mortal. II. Some mortals are men.