Verbal Reasoning - Mental Ability Questions

P is the brother of Q. Q is the brother of R. P is the son of S. Based these three statements, much of the following statements cannot be definitely true?

A is D's brother. D is the son of Mrs. C. B is Mrs. C's father. How is A related to B?

How is Sameer related to Akbar if Sameer introduced Akbar as his maternal grandmother's only son's son?

In the following question, which one set of letters when sequentially placed at the gaps in the given letter series shall complete it?
a _ bc _ a _ bcdabc _ da _ cd _

In a certain code language, '+' represents 'x', '-' represents '+', 'x' represents '÷' and '÷' represents '-'. What is the answer to the following question?

45 x 5 + 2 - 20 = ?

In the following question, select the related word from the given alternatives.
Ampere : Electric current : : Fathom : ?

Ram said , "Sita is my paternal great grandfather's only son's only daughter-in-law". How is Sita related to Ram?

In the following question, select the related word pair from the given alternatives. Lotus : Flower : : ? : ?