Table of contents  
What is a Series / Sequence?  
Numerical Series  
Alphabet Series  
Mixed Series  
Series Consisting of Letters, Numbers and Symbols  
Miscellaneous Type Questions 
A series or sequence consists of several terms. In other words, the unit of a sequence is called a term. Each term in the series has its own importance as there exists a certain relationship between the two consecutive/alternating terms.
Ex: 1, 3, 5, 7, 9, 11, ……. The difference between two consecutive numbers is 2. So it makes a series.
Ex: 1, 2, 4, 7, 11, 16……. The difference between the consecutive number is 1, 2, 3, 4, 5 and so on it also makes a perfect series.
Example 1: Which is the number that comes next in the sequence?
1, 5, 13, 29, __ , 125
(a) 32
(b) 62
(c) 61
(d) 31The correct answer is option (c).
Sol. In this case, the series is increasing by +4, +8, +16, +32, +64. So our answer is 61, as by adding the number 32 to 29 we get the required number, i.e. 61.
Example 2: 1, 4, 9, 16, 25, __ ?(a) 35
(b) 36
(c) 48
(d) 49The correct answer is option (b).
Sol. The numbers are: 1^{2}, 2^{2}, 3^{3}, 4^{2}, 5^{2}
Hence 6^{2} = 36.
Example 3: Which is the number that comes next in the sequence?6, 11, 21, 36, 56, __
(a) 42
(b) 51
(c) 81
(d) 91The correct answer is option (c).
The answer here is 81 because the series is progressing by a factor of 5,10,15, 20, 25.
Example 4: Which is the number that comes next in the sequence?0, 6, 24, 60, 120, 210, ___ ?
(a) 240
(b) 290
(c) 336
(d) 504The correct answer is option (d).
Sol. Clearly, the given series is: 1^{3} – 1, 2^{3} – 2, 3^{3} – 3, 4^{3} – 4, 5^{3} – 5, 6^{3} – 6.
Next number = 7^{3} – 7 = 343 – 7 = 336.
Example 5: What terms will fill the blank spaces?
A, B, C, D, E, (….), (….) (a) O, K
(b) N, M
(c) K, S
(d) F, GThe correct answer is option (d).
Sol. The given series consists of alphabets in their original order. So, the missing terms would be (d) F and G.
Example 6: What terms will fill the blank spaces?Z, X, V, T, R, (…), (…)
(a) O, K
(b) N, M
(c) K, S
(d) P, NThe correct answer is option (d).
Sol. Clearly, the given series consists of alternate letters in reverse order. The alphabets are skipped one at a time. So, the missing terms would be (d) P and N.
Example 7: Find the missing alphabet: B, D, G, K, P, (…), (…)Sol. Each time the number of letters skipped increases by one. So the answer here is V.
B is the second alphabet in the series, D is fourth in the series, G is seventh, K is eleventh, P is sixteenth and so the next will be twenty second i.e. V of the series.
Example 8: Find the missing term:
OTE, PUF, QVG, RWH, (….)(a) SYJ
(b) TXI
(c) SXJ
(d) SXIThe correct answer is option (d).
Sol. The first letters of the terms are in alphabetical order, and so are second and third letters.
OPQRS, TUVWX, EFGHI
Directions (9– 10): Study the following arrangement carefully and answer the questions given below:
W 1 5 E J R 2 M A 9 T K U N 4 B I 8 D H 3 F 6 P Z 7 Q
Example 9: How many such consonants are there, each of which is immediately preceded by a number and immediately followed by a vowel?
(a) None
(b) One
(c) Two
(d) ThreeThe correct answer is option (c).
Example 10: Which of the following is the seventh to the left of 4?
(a) M
(b) A
(c) F
(d) 3The correct answer is option (a).
Directions (11 –12): Study the following arrangement carefully and answer the questions given below :
K P 5 # 7 M N E 2 D A ¶ 4 F H I T 9 1 $ U 6% W 3
Example 11: How many such vowels are there in the above arrangement, each of which is either immediately preceded by a number or immediately followed by a symbol?(a) None
(b) One
(c) Two
(d) ThreeThe correct answer is option (b).
Example 12: Which of the following is the sixth to the right of the fifteenth element from right end in the above arrangement?
(a) T
(b) 7
(c) 2
(d) UThe correct answer is option (a).
15^{th} element from right Þ A
6^{th} to right of A Þ T
Required element =15 – 6 = 9^{th} term from right.
5 8 # B F L E 4 * M J 9 G N 2 W 3 + S 4 ? $ P Q 6 R 7 & H T
How many symbols are there which are immediately preceded by a number and immediately followed by a letter?
Example 13: How many such digits are there in the number 82134967 each of which is as far away from the beginning of the number as when they are arranged in descending order?
(a) None
(b) One
(c) Two
(d) ThreeThe correct answer is option (b).
4 is such number in the series which is at the same position in the original and also when arranged in descending order.
1365 videos1312 docs1010 tests

1. What is a numerical series? 
2. What is an alphabet series? 
3. What is a mixed series? 
4. What are the types of series consisting of letters, numbers, and symbols? 
5. How can one prepare for solving series questions in exams? 
1365 videos1312 docs1010 tests


Explore Courses for SSC CGL exam
