In the sequence $7, 8, 9, 7, 6, 5, 3, 4, 2, 8, 9, 7, 2, 4, 5, 9, 2, 9, 7, 6, 4, 7$,how many $7$'s are preceded by $9$ and followed by $6$?

$(I)$ Kamal is available at home from $12$ noon to $4 \,p.m.$ on Tuesday,Thursday,and Sunday.
$(II)$ His younger brother Navin is available at home on Monday,Thursday,Friday,and Sunday between $10 \,a.m.$ to $2 \,p.m.$
$(III)$ The eldest brother Rajiv is available between $9 \,a.m.$ to $12$ noon on Monday,Wednesday,and Thursday and $2 \,p.m.$ to $4 \,p.m.$ on Friday,Saturday,and Sunday.
For how many days is only one brother available at a particular time in a week?

In a row of boys,Deepak is seventh from the left and Madhu is twelfth from the right. If they interchange their positions,Deepak becomes twenty-second from the left. How many boys are there in the row?

Mohan is older than Prabir,Suresh is younger than Prabir. Mihir is older than Suresh but younger than Prabir. Who among the four is the youngest?

In a school,the following codes were used during physical exercise. $1$ means 'start walking',$2$ means 'keep standing',$3$ means 'start running at the same spot',$4$ means 'sit down'. How many times will a student who performs the following sequence without error from the beginning to the end have to sit down?
$1, 2, 3, 4, 2, 3, 1, 4, 4, 3, 2, 2, 1, 2, 4, 3, 1, 4, 4, 1, 2$

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?