$A$ is elder to $B$ while $C$ and $D$ are elder to $E$ who lies between $A$ and $C$. If $C$ is elder to $B$,which one of the following statements is necessarily true?

After interchanging seats with $E$,who will be the neighbours of $D$ in the new position?

In a school,there were five teachers. $A$ and $B$ were teaching Hindi and English. $C$ and $B$ were teaching English and Geography. $D$ and $A$ were teaching Mathematics and Hindi. $E$ and $B$ were teaching History and French. More than two teachers were teaching which subject?

Rohit,Kunal,Ashish,and John are students of a school. Three of them stay far from the school and one near it. Two study in class $IV$,one in class $V$,and one in class $VI$. They study Hindi,Mathematics,Social Science,and Science. One is good at all the four subjects while another is weak in all of these. Rohit stays far from the school and is good at Mathematics only,while Kunal is weak in Mathematics only and stays close to the school. Neither of these two nor Ashish studies in class $VI$. One who is good at all the subjects studies in class $V$. Which two boys are good at Mathematics?

$B$ is twice as old as $A$ but twice younger than $F$. $C$ is half the age of $A$ but twice the age of $D$. Which two persons form the pair of oldest and youngest?

There are five bus stops $A, B, C, D,$ and $E$ at equal intervals. $C$ is not the middle stop. $A$ and $E$ are not terminal stops. $C$ comes twice as many stops before $D$ in the upward journey as $B$ comes after $A$. $D$ is the first stop in the downward journey. Which of the following gives the correct sequence of the stops in the downward journey?