Verbal Reasoning - Mental Ability Questions

Which one set of letters when sequentially placed at the gaps in the given letter series shall complete it?

xy_kx_zk_yzk xyz_ _

A series is given, with one number missing. Choose the correct alternative from the given ones that will complete the series.
6, 18, 54, ? , 486, 1458

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

5 , 11 , 24 , 51 , 106 ,____?

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

AK, DQ, GV, JZ, ?

In the following question, select the related number from the given alternatives.
49 : 169 : : 66 : ?

In a certain code language, "BAD" is written as "7" and "SAP" is written as "9". How is "BAN" written in that code language?

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

FU, HS, JQ, ?

$$\begin{gathered} If (─) stands for division, (+) stands for multiplication, (÷) stands for subtraction and \\ (×) stands for addition, which one of the following equations is correct? \end{gathered}$$