Akshay is $16^{th}$ from the left end in a row of boys and Vijay is $18^{th}$ from the right end. Avinash is $11^{th}$ from Akshay towards the right end and $3^{rd}$ from Vijay towards the right end. How many boys are there in the row?

Aruna ranks twelfth in a class of forty-six. What will be her rank from the last?

In the following list of numerals,how many $2$'s are followed by $1$'s but not preceded by $4$?

In a row of girls,Rita and Monika occupy the ninth place from the right end and tenth place from the left end,respectively. If they interchange their places,Rita and Monika occupy seventeenth place from the right and eighteenth place from the left,respectively. How many girls are there in the row?

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?

How many $3$s are there in the following number sequence which are immediately preceded by $6$ but not immediately followed by $7$?
$2, 3, 7, 4, 3, 5, 6, 3, 7, 4, 6, 3, 8, 9, 6, 5, 1, 8, 3, 7, 2, 4, 2, 8, 6, 3, 9$