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?

If the numbers from $1$ to $45$ which are exactly divisible by $3$ are arranged in ascending order,with the minimum number at the top,which number would be at the ninth place from the top?

Given the series: $7, 8, 9, 7, 6, 5, 3, 4, 2, 8, 9, 7, 2, 4, 5, 9, 2, 9, 7, 6, 4, 7$. Which numbers have equal frequency?

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?

How many even numbers are there in the following sequence of numbers which are immediately followed by an odd number as well as immediately preceded by an even number?
$8, 6, 7, 6, 8, 9, 3, 2, 7, 5, 3, 4, 2, 2, 3, 5, 5, 2, 2, 8, 1, 1, 9$

Among five friends,Mahesh is taller than Karan but not Yash. Hrithik is taller than Yash but not Abhishek. If they stand in increasing order of their heights,who will be first in line?