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
6.

Look at this series: VI, 10, V, 11, __, 12, III, … What number should fill the blank?
A.     II    B.     IV
C.     IX    D.     14
Answer & Explanation

Answer: Option B

Explanation:

This is an alternating addition and subtraction series. Roman numbers alternate with Arabic numbers. In the Roman numeral pattern, each number decreases by 1. In the Arabic numeral pattern, each number increases by 1.
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7.

Look at this series: (1/9), (1/3), 1, ____ , 9, … What number should fill the blank?
A.     (2/3)    B.     3
C.     6    D.     27
Answer & Explanation

Answer: Option B

Explanation:

This is a multiplication series; each number is 3 times the previous number.
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8.

Look at this series: 83, 73, 93, 63, __, 93, 43, … What number should fill the blank?
A.     33    B.     53
C.     73    D.     93
Answer & Explanation

Answer: Option B

Explanation:

This is a simple subtraction series in which a random number, 93, is interpolated as every third number. In the subtraction series, 10 is subtracted from each number to arrive at the next.
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9.

Look at this series: 15, __, 27, 27, 39, 39, … What number should fill the blank?
A.     51    B.     39
C.     23    D.     15
Answer & Explanation

Answer: Option D

Explanation:

In this simple addition with repetition series, each number in the series repeats itself, and then increases by 12 to arrive at the next number.
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10.

Look at this series: 72, 76, 73, 77, 74, __, 75, … What number should fill the blank?
A.     70    B.     71
C.     75    D.     78
Answer & Explanation

Answer: Option D

Explanation:

This series alternates the addition of 4 with the subtraction of 3.