Verbal Reasoning - Mental Ability Questions

In the following question, select the related letters from the given alternatives.
PRAG : QTDK : : STOP : ?

Choose the related word/letters/number from the given alternatives.
NPR : GHI : : TVX : ?

A man walks 7 km towards south and turns to the left. After walking 5 km, he turns to the right and walks 7 km. In which direction is he now from the starting point?

If "#" means "subtraction", "&" means "division", "@" means "addition" and "%" means "multiplication", then 315&3#9@4%6 = ?

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

AZ, BY, CX, ?

If 'P 3 Q' means 'P is daughter of Q', 'P 5 Q' means 'P is father of Q', 'P 7 Q' means 'P is mother of Q' and 'P 9 Q' means 'P is sister of Q', then how is J related to K in J 3 L 9 N 3 O 5 K?

In the following question, select the related word from the given alternatives.
Book : Pages : : Continent : ?

A series is given, with one number missing. Choose the correct alternative from the given ones that will complete the series.
400, -200, 100, ? , 25, -12.5