How many numbers from $11$ to $50$ are there which are exactly divisible by $7$ but not by $3$?

How many $3$'s are there in the following sequence which are neither preceded by $6$ nor immediately followed by $9$?
$9, 3, 6, 6, 3, 9, 5, 9, 3, 7, 8, 9, 1, 3, 9, 6, 3, 9$

In the series,$6, 4, 1, 2, 2, 8, 7, 4, 2, 1, 5, 3, 8, 6, 2, 1, 7, 1, 4, 1, 3, 2, 8, 6$,how many pairs of successive numbers have a difference of $2$ each?

In a row of boys,Kapil is $8^{th}$ from the right and Nikunj is $12^{th}$ from the left. When Kapil and Nikunj interchange positions,Nikunj becomes $21^{st}$ from the left. Which of the following will be Kapil's position from the right?

In the Olympic Games,the flags of six nations were flown on the masts in the following way: The flag of America was to the left of the Indian tricolour and to the right of the flag of France. The flag of Australia was on the right of the Indian flag but was to the left of the flag of Japan,which was to the left of the flag of China. Find the two flags which are in the centre.

Sanal's position in a row is $12^{th}$ from the front side and $47^{th}$ from the back side. How many persons are standing in that row?