Verbal Reasoning - Mental Ability Questions

In a certain code language, "SCENE" is written as "TBFMF". How is "TRAIN" written in that code language?

A series is given, with one number missing. Choose the correct alternative from the given ones that will complete the series.
400, -200, 100, ? , 25, -12.5

Select the related number from the given alternatives.
12.5 : 6.25 :: 7 : ?

Select the related word/letters/number from the given alternatives.
ACE : HJL:: LNP : ?

Which one set letters when sequentially placed at the gaps in the given letter series shall complete it?

M__OMMN__M__NOMMN__M

What number should come in place of ?

Find the next number in the given series. 9, 11, 15, 17, 21, 23, ?

If "S" denotes "multiplied by", "V" denotes "subtracted from", "M" denotes "added to" and "L" denotes "divided by", then 7 V 42 M 56 L 8 S 5 = ?