Fill in the blank space for the given series with the correct alternative.
$66, 36, 18, (...)$

What terms will fill the blank spaces?
$Z, X, V, T, R, (...), (...)$

Fill in the blank space for the given series with the correct alternative.
$0.5, 1.5, 4.5, 13.5, (\ldots)$ (in $.5$)

How many such numbers are there in the following series,each of which is immediately preceded by $6$ but not immediately followed by $4$?
$3, 8, 6, 8, 4, 2, 6, 9, 8, 4, 6, 8, 4, 8, 6, 2, 6, 8, 4, 8$

The positions of how many digits in the number $7,3,5,4,6,1,2$ will remain unchanged after the digits within the number are rearranged in descending order from left to right?

Second and third digits of each number given below are interchanged. Then,the $1st$ and the last digits of each new number thus formed are interchanged. Which of the following numbers then will be the highest number among the five?
$273, 372, 438, 184, 526$