Among $B, F, J, K$ and $W$ each having a different weight, $F$ is heavier than only $J.$ $B$ is heavier than $F$ and $W$ but not as heavy as $K.$ Who is the third heaviest among them?

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

How many numbers between $9$ and $54$ (inclusive) are exactly divisible by $9$ but not by $3$?

In the series given below,count each $5$ which is not immediately preceded by $3$ but is immediately followed by $7$. How many such $5$ are there?
$1, 5, 7, 3, 5, 7, 4, 7, 3, 7, 2, 5, 6, 5, 8, 5, 7, 4, 5, 6, 5, 5, 7, 1, 5, 7, 7, 5, 5$

Satish remembers that his brother's birthday is after $15^{th}$ but before $18^{th}$ of February,whereas his sister Kajal remembers that her brother's birthday is after $16^{th}$ but before $19^{th}$ of February. On which day in February is Satish's brother's birthday (in $^{th}$)?

If the first and second digits in the sequence $5, 9, 8, 1, 3, 2, 7, 4, 3, 8$ are interchanged,also the third and fourth digits,the fifth and sixth digits and so on,which digit would be the seventh counting to your left?