3240, 540, 108, 27, ? , 4.5

Direction: What should come in place of the question mark (?) in the following number series?
0.5, 2, 9, 35, 104, ?

If a, b and c are in GP and a^1/x=b^1/y=c^1/z. The value of 2y is?

If a , b , c are in AP and x , y and z are in GP , then $${x^{b-c}.{y^{c-a}.z^{a-b}=?}}$$

Direction : What should come in place of the question (?) in the following question.

16  8    12   30  ?    472.5

Direction : What should come in place of the question (?) in the following question.

15  34    20   ?   25    43  30

Direction (66-70): What should come in place of the question mark(?) in the following number series?

10    11    13    21    69    ?