List of top Logical Reasoning Questions on Series

A set of letters and numbers are arranged in certain order where some of them are missing. \[ 1 \quad \_ \quad 7g \quad \_ \quad c8 \quad \_ \quad \_ \quad b \] Choose the correct order of appearing in the missing places.

Look at this number series: 2, 6, 18, 54, ... What number should come next?

E N 3 G # B S 5 A L 9 $ # 7 % U 4 Q K I P 2 @ 8 Y

How many such consonants are there in the above sequence each of which is immediately followed by a number and immediately preceded by a vowel?

What should come in place of question mark (?) in the following number/alphabetic series?
X U S P N K ?