# Logical Reasoning - Number Series

### Exercise :: Number Series - Type 4

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