Among $P,$ $Q,$ $R,$ $S,$ and $T,$ $S$ is older than $R$ but not as old as $T.$ $Q$ is older than only $P.$ Who among them is the youngest?

Raman ranks sixteenth from the top and forty-ninth from the bottom in a class. How many students are there in the class?

In the sequence $5, 1, 4, 7, 3, 9, 8, 5, 7, 2, 6, 3, 1, 5, 8, 6, 3, 8, 5, 2, 2, 4, 3, 4, 9, 6$,how many even numbers are there which are immediately preceded by an odd number and immediately followed by an even number?

How many $18$s are there in the following sequence which are immediately preceded by $9$ but not immediately followed by $7$?
$7, 1, 9, 1, 1, 7, 1, 8, 9, 1, 7, 1, 2, 1, 3, 1, 4, 5, 7, 1, 3, 9, 1, 7$

How many numbers from $1$ to $100$ are there,each of which is not only exactly divisible by $4$ but also has $4$ as a digit?

In a row of $40$ students facing North, Kailash is $6^{th}$ to the left of Soman. If Soman is $30^{th}$ from the left end of the row, how far is Kailash from the right end of the row (in $^{th}$)?