List of top Logical Reasoning Questions on Series

AB, BA, ABC, CBA, ABCD, ?
OTE, PUF, QVG, RWH,?
A, Z, X, B, V, T, C, R, ?, ?
Identify the missing number:
1 and 3, 4 and 6, 7 and 9, …. and 12
20, 30, 42, 56, 72, ____
53, 50, 45, 38, 29, ____

Fill in the blank: 
257, 291, ______, 365, 405

Fill in the blank:
Q4RT, ______, QRT6, QR7T, Q8RT
Identify the missing number:
1 and 3, 4 and 6, 7 and 9, ___ and 12
If \(1 × 7 = 8, 2 × 7 = 16, 3 × 7 = 24, 4 × 7 = 32\), then what is value of \(9 × 7\)?
Examine the following numbers and identify the next number:
20, 30, 42, 56, 72, ____
Examine the following numbers and identify the next number:
53, 50, 45, 38, 29, _____
Fill in the blank :
257, 291, ______ , 365, 405
Fill in the blank :
Q4RT, ______ , QRT6, QR7T, Q8RT