What should come next in the following letter sequence?

A A B A B C A B C D A B C D E A B C D

How many meaningful English words can be formed with the letters ESRO using each letter only once in each word?

Of the six members of a panel sitting in a row  X is to left of Q but on the right  of P. Y is in the right of Q but is on the left of Z, Z is to the left of R. Find the members who are at the extreme?

How many A's are there in the following sequence which are immediately followed by B as well as immediately preceded by Z?

A M B Z A N A A B Z A B A Z B A P Z A B A Z A B 

In the following Colour sequence, R stands for Red, Y for Yellow , G for Green, B for Blue and W for white of the sequence is continued, which colour will come next?

B B R B R W B R W G B R W G Y B R B R W B R W

If the first and third letters in the word 'ANNIHILATION' are interchanged , also the second and fourth, the fifth and seventh and so on, then which of the following letter would be the 6th from the left?

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z .

Which letter in this alphabet is the eighth letter to the right of the letter and  which is tenth letter to the left of the last but one letter of the alphabet?

How many pairs of letters are there in the word " CASTRAPHONE" which have as many letters between them in the word as in the alphabet?

If it is possible to form a word with the first , fourth, seventh and eleventh letters in the word "SUPERFLUOUS" write the first letter of that word. other wise x is the answer.