Some boys are sitting in a row. $P$ is sitting fourteenth from the left and $Q$ is seventh from the right. If there are four boys between $P$ and $Q,$ how many boys are there in the row?

In a row of $21$ girls, when Anita was shifted by four places towards the right, she became $12^{th}$ from the left end. What was her earlier position from the right end of the row (in $^{th}$)?

Three persons $A, B$ and $C$ are standing in a queue. There are $5$ persons between $A$ and $B$ and $8$ persons between $B$ and $C$. If there are $3$ persons ahead of $C$ and $21$ persons behind $A$, what could be the minimum number of persons in the queue?

In the following sequence of instructions,$1$ stands for Run,$2$ stands for Stop,$3$ stands for Go,$4$ stands for Sit and $5$ stands for Wait. If the sequence were continued,which instruction will come next?
$4, 4, 5, 4, 5, 3, 4, 5, 3, 1, 4, 5, 3, 1, 2, 4, 5, 4, 5, 3, 4, 5, 3$

If $18^{th}$ February,$1997$ falls on Tuesday,then what will be the day on $18^{th}$ February,$1999$?

In a row of girls, Shilpa is $8^{th}$ from the left and Reena is $17^{th}$ from the right. If they interchange their positions, Shilpa becomes $14^{th}$ from the left. How many girls are there in the row?