# number series logical reasoning questions

11.

Look at this series: J14, L16, __, P20, R22, … What number should fill the blank?
A.     S24    B.     N18
C.     M18    D.     T24

Explanation:

In this series, the letters progress by 2, and the numbers increase by 2.
12.

Look at this series: 4, 7, 25, 10, __, 20, 16, 19, … What number should fill the blank?
A.     13    B.     15
C.     20    D.     28

Explanation:

Two series alternate here, with every third number following a different pattern. In the main series, 3 is added to each number to arrive at the next. In the alternating series, 5 is subtracted from each number to arrive at the next.
13.

Look at this series: XXIV, XX, __, XII, VIII, … What number should fill the blank?
A.     XXII    B.     XIII
C.     XVI    D.     IV

Explanation:

This is a simple subtraction series; each number is 4 less than the previous number.
14.

Look at this series: 0.15, 0.3, ____, 1.2, 2.4, … What number should fill the blank?
A.     4.8    B.     0.006
C.     0.6    D.     0.9

Explanation:

This is a simple multiplication series. Each number is 2 times greater than the previous number.
15.

Look at this series: U32, V29, __, X23, Y20, … What number should fill the blank?
A.     W26    B.     W17
C.     Z17    D.     Z26

Explanation:

In this series, the letters progress by 1; the numbers decrease by 3.