What is the next letter is series A F Z U G L T?

Answer 1

Answer is "o" because

a(first letter)-F(6th letter)=different of 5 x+y

difference z to u = 5 x-y

difference g to l i= 5 x+y

difference t to o = 5 x-y

Answer 2

O -- If you represent each letter by a number representing its place in the alphabet, then pairs of letters two places apart in the sequence add up to 27.

The next block of four letters would be MRNI, because you start a new block with letters that are 6 places later in the alphabet than the one that comes four places earlier in the sequence

Answer 3

o