# 3rd Class Mental Ability Series

Series

Category : 3rd Class

Series

Learning Objectives

• Number Series
• Letter Series
• Mixed Series

Number Series

A number series is a sequence of many elements made of numbers only. Such sequence is formed by putting the numbers one after another from left to right.

Properties of Number Series

(1) A number series can be in forward or reverse order.

(2) A number series can be in random order.

(3) A single number series can have more than one series.

Example-1

1. Find the missing number in the following series. (a) 9                              (b) 8

(c) 7                             (d) 5

(e) None of these

Explanation: Option (d) is correct because the series goes as following:

1 + 1 = 2

2 + 1 = 3

3 + 1 = 4

4 + 1 = 5 + 1 = 6

Rest of the options is incorrect because of the correctness of option (d).

2.            Find the next number. (a) 6                                          (b) 5

(c) 7                                          (d) 4

(e) None of these

Explanation:

Let us see: Rest of the options is incorrect because of the correctness of option (a).

3.           Find the missing number in the following series. (a) 12                           (b) 11

(c) 13                           (d) 15

(e) None of these

Explanation: Rest of the options is incorrect because of the correctness of option (c).

4.            What will come in place of the blank space? (a) 26                                        (b) 25

(c) 23                                        (d) 24

(e) None of these

Explanation: Option (c) is correct because the series goes as following:

21 + 2 = 23 + 2 = 25

25 + 2 = 27

27 + 2 = 29

Rest of the options is incorrect because of the correctness of option (c).

5.           Find the missing number in the series given below. (a) 8                              (b) 7

(c) 6                              (d) 4

(e) None of these

Explanation: Option (b) is correct because the series goes as following:

15 – 2 = 13

13 - 2 = 11

11 – 2 = 9

9 – 2 = 7 – 2 = 5

Rest of the options is incorrect because of the correctness of option (b).

1. Find the next number in the series given below. (a) 19                           (b) 18

(c) 17                           (d) 15

(e) None of these

Explanation: Rest of the options is incorrect because of the correctness of option (c).

2.           Find the missing number in the series given below. (a) 15                           (b) 16

(c) 17                           (d) 19

(e) None of these

Explanation: Option (b) is correct because the series goes as following:

12+2=14

14 + 2 = 16 + 2 = 18

18 + 2 = 20

Rest of the options is incorrect because of the correctness of option (b).

3.           What comes next in the following series? (a) 6                             (b) 8

(c) 9                             (d) 7

(e) None of these

Explanation: Rest of the options is incorrect because of the correctness of option (d).

4.           What comes next in the following series? (a) 10                           (b) 12

(c) 15                           (d) 13

(e) None of these

Explanation: Rest of the options is incorrect because of the correctness of option (d).

5.         What comes next in the following series? (a) 4                             (b) 6

(c) 5                             (d) 8

(e) None of these

Explanation: Rest of the options is incorrect because of the correctness of option (c).

Letter Series

A letter series is a sequence of many elements made of letters of English alphabet only

Properties of Letter series

(1) A letter series can be in forward order,

(2) A letter series can be in reverse order.

(3) A letter series can be in random or jumbled order.

Example-2

1. Find the next letter in the series. (a) H                                         (b) G

(c) I                               (d) J

(e) None of these

Explanation: The answer is G, because the pattern is to count forward from the given first letter: Rest of the options is incorrect because of the correctness of option (b).

2.            Find the missing letter in the series. (a) Y                                         (b) Z

(c) P                             (d) T

(e) None of these

Explanation: The answer is T, because the pattern is to count backwards: Rest of the options is incorrect because of the correctness of option (d).

3.            Find the next letter in the series. (a) J                             (b) K

(c) L                             (d) H

(e) None of these

Explanation: Rest of the options is incorrect because of the correctness of option (b).

4.         Find the next letter in the series. (a) T                             (b) U

(c) H                                         (d) G

(e) None of these

Explanation: 1st series: D E F G (forward order series)

2nd series: Z Y X W (reverse order series)

Rest of the options is incorrect because of the correctness of option (d).

5.          Find the missing term in the series given below. (a) NM                          (b) NP

(c) MO                          (d) MN

(e) None of these

Explanation: Rest of the options is incorrect because of the correctness of option (d).

1.            Find the next letter in the series. (a) y                                          (b) D

(c) C                                         (d) W

(e) None of these

Explanation: Rest of the options is incorrect because of the correctness of option (c).

2.            Find the next letter in the series. (a) S                             (b) P

(c) R                             (d) Q

(e) None of these

Explanation: Rest of the options is incorrect because of the correctness of option (a).

3.           Find the next pair of letter in the series. (a) GQ                          (b) HQ

(c) IQ                           (d) GR

(e) None of these

Explanation: Rest of the options is incorrect because of the correctness of option (a).

4.            Find the missing letter. (a) L                             (b) O

(c) P                             (d) Q

(e) None of these

Explanation: Rest of the options is incorrect because of the correctness of option (d).

5.            Find the missing letter. (a) R                             (b) Q

(c) O                            (d) P

(e) None of these

Explanation: Rest of the options is incorrect because of the correctness of option (c).

Mined Series

A mixed series is a sequence of many elements made of numbers and letters arranged from left to right. In other words, we can say that a mixed series is sequence of diverse elements.

Example-3  1.            Find the next elements in the series given below.

A 2 B 3 C 4 D 5 (a) F6                                        (b) E6

(c) 16                                        (d) 6F

(e) None of these

Explanation: Option (b) is correct because in the given series, letters and numbers take place alternately. Every next letter is one letter ahead from the previous letter and every next number/digit gets increased by 1.

Rest of the options is incorrect because of the correctness of option (b).

2.           What comes next in the series given below? (a) 3D                          (b) D3

(c) E3                                        (d) 3E

(e) None of these

Explanation: Option (b) is correct because in this series', numbers and letters take place alternately. Every next number decreases by 1 and every next letter is one letter ahead form the previous letter.

Rest of the options is incorrect because of the correctness of option (b).

3.            What comes in place of the blank space? (a) J12                                      (b) l13

(c) J13                                       (d) l12

(e) None of these

Explanation: Option (b) is correct because of the following reason. 1st series (Number series):     A C E G I

Every next letter of this series takes place skipping one letter in forward alphabetical order.

Let us see: 2nd series (Number series):     5 7 9 11 13

Clearly, every next element of this series increases by 2.

Let us see:

5 + 2 = 7

7 + 2 = 9

9 + 2 = 11

11 + 2 = 13

Rest of the options is incorrect because of the correctness of option (b).

4.          Fill the blank space. (a) 11B                         (b) 13B

(c) B12                         (d) 12B

(e) None of these

Explanation: Option (b) is correct because the given series is in the reverse order in which numbers and letters take place alternately. Every next number decreases by 1 and every next letter is one letter backward from the previous letter.

Rest of the options is incorrect because of the correctness of option (b).

5.

1. Find the missing element in the series given below.

a b 3 4 c d 5 6 e f 7 8 g ? ? 1 0

(a) 9, h                          (b) 9, i

(c) i, 9                          (d) h, 9

(e) None of these

Explanation: Option D is correct because in the given series, Rest of the options is incorrect because of the correctness of option (d).

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