number series logical reasoning questions

Find the number that fits somewhere into the middle of the series. Some of the items involve both numbers and letters
1.

Look at this series: F2, __, D8, C16, B32, … What number should fill the blank?
A.     A16    B.     G4
C.     E4    D.     E3
Answer & Explanation

Answer: Option C

Explanation:

The letters decrease by 1; the numbers are multiplied by 2.
View Answer Workspace Report Discuss in Forum
2.

Look at this series: 664, 332, 340, 170, ____, 89, … What number should fill the blank?
A.     85    B.     97
C.     109    D.     178
Answer & Explanation

Answer: Option D

Explanation:

This is an alternating division and addition series: First, divide by 2, and then add 8.
View Answer Workspace Report Discuss in Forum
3.

Look at this series: V, VIII, XI, XIV, __, XX, … What number should fill the blank?
A.     IX    B.     XXIII
C.     XV    D.     XVII
Answer & Explanation

Answer: Option D

Explanation:

This is a simple addition series; each number is 3 more than the previous number.
View Answer Workspace Report Discuss in Forum
4.

Look at this series: 70, 71, 76, __, 81, 86, 70, 91, … What number should fill the blank?
A.     70    B.     71
C.     80    D.     96
Answer & Explanation

Answer: Option A

Explanation:

In this series, 5 is added to the previous number; the number 70 is inserted as every third number.
View Answer Workspace Report Discuss in Forum
5.

Look at this series: 8, 43, 11, 41, __, 39, 17, … What number should fill in the blank?
A.     8    B.     14
C.     43    D.     44
Answer & Explanation

Answer: Option B

Explanation:

This is a simple alternating addition and subtraction series. The first series begins with 8 and adds 3; the second begins with 43 and subtracts 2.