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 $35$ children,$M$ is $15^{th}$ from the right end and there are $10$ children between $M$ and $R.$ What is $R$'s position from the left end of the row?

In the following series,how many such odd numbers are there which are divisible by $3$ or $5$,followed by an odd number,and then followed by an even number?
$12, 19, 21, 3, 25, 18, 35, 20, 22, 21, 45, 46, 47, 48, 9, 50, 52, 54, 55, 56$

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

$A$ number is greater than $3$ but less than $8$. Also,it is greater than $6$ but less than $10$. The number is

In a row of $40$ students facing North, Kailash is $6^{th}$ to the left of Soman. If Soman is $30^{th}$ from the left end of the row, how far is Kailash from the right end of the row (in $^{th}$)?