Which letter should come next in the series F,G,H,J,K,L,M,N,P,__________?

Q

The following table shows the position values of the alphabets:

Answer will be Q

As, we can see that there is no pattern observed, we need to think in different way, In most of the cases if there is no numerical pattern, we will observe pattern in terms of alternates series or pattern relating to vowels and consonants. 

In the above series, all the consecutive consonants have been placed in increasing order, so Q should come next in the series.

We can also memorize the alphabets so that we do not do any calculation mistakes and also reduce the time to solve answers: