Verbal Reasoning - Mental Ability Questions

In the following question, select the related letters from the given alternatives.
JQXE : LSZG : : MTNL : ?

A series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.

RP, DM, SQ, CL, TR, ?

Some books are arranged one above the other. If a book is at 18th position from the top and 5th position from bottom then the total number of books is

M is son of P, Q is the grand-daughter of O, who is the husband of P. How is M related to O?

In a certain code language, “LUNGS” is written as “OWQIV”. How is “HEART” written in that code language?

Pointing towards a girl, Chetan said "She is the daughter of the only child of my grandmother". How is Chetan related to that girl?

Select the related word/letters/number from the given alternatives.
Farmer : Plough:: Painter: ?

A series is given, with one word missing. Choose the correct alternative from the given ones that will complete the series.

hello, lower, error, organ, tense, ?