What should come next in the following letter series based on English alphabet?

    CEA                   IKG                    OQM                     ?

Reasoning:

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

Reasoning:

In a certain code, ‘3 4 5’ means ‘come and go’ and ‘5 9 7’ means ‘go back now’. What does ‘9’ mean in that code?

Reasoning:

If ‘M’ denotes ‘+’, ‘N’ denotes ‘/’, ‘R’ denotes ‘-‘and ‘Q’ denotes ‘x’, then

    15  M  12  Q  5  R  40  N  8  = ?

Reasoning:

M earns more than X and less than T. V earns more than M and T. R earns more than only X. who earns the least among the five of them? 

Reasoning:

The positions of how many digits in the number 53269718 will remain unchanged if the digits within the number are rearranged in ascending order?

Reasoning:

The positions of the first and the fifth digits in the number 89123654 are interchanged. Similarly, the positions of the second and the sixth digits are interchanged and so on. Which of the following will be the second digit from the right end after the rearrangement? 

Reasoning:

What should come next in the following letter series based on English alphabet?

    CEA                   IKG                    OQM                     ?

Reasoning:

If ‘/’ means ‘+’; ‘-‘means ‘x’; ‘x’ means ‘/’ and ‘+’ means ‘-‘; then

      15 – 8 x 6 / 12 + 4 = ?

Reasoning:

Srinivas correctly remembers that his mother’s birthday is before twenty-third April but nineteenth April, whereas his sister correctly remembers that their mother’s birthday is not on or after twenty-second April. On which day in April is definitely their mother’s birthday? 

Reasoning:

M is brother of K. T is sister of K. R is father of M. J is wife of R. How many sons does J have?