Series questions test whether you can identify the rule connecting a sequence of numbers, letters, or combined elements. In SNAP, they may appear within the Analytical and Logical Reasoning section and can often be solved quickly once the underlying pattern is recognised.
What Are Series Questions in SNAP?
A series question presents a sequence in which each term follows a mathematical or logical relationship. You may be asked to find the next term, identify a missing term, locate an incorrect term, or complete a repeating pattern.
For example:
3, 6, 12, 24, ?
Each term is twice the preceding term, so the answer is 48.
Although the rule is simple in this example, SNAP-style aptitude questions may combine operations, alternate between two patterns, or use alphabet positions.
Types of Series Questions
| Series type | What to check | Simple example |
|---|---|---|
| Constant difference | Add or subtract the same value | 5, 9, 13, 17 |
| Changing difference | Differences increase or decrease systematically | 2, 5, 9, 14 |
| Multiplication or division | Terms grow or fall rapidly | 3, 9, 27, 81 |
| Mixed operation | Multiply or divide, then add or subtract | 4, 10, 22, 46 |
| Square or cube pattern | Terms resemble perfect powers | 2, 9, 28, 65 |
| Alternating series | Odd and even positions follow separate rules | 10, 5, 15, 10, 20 |
| Letter series | Alphabet positions follow a pattern | A, C, F, J |
| Alphanumeric series | Letters and numbers follow connected or parallel rules | A1, C3, F6 |
| Cyclic pattern | A group repeats or rotates | ABC, BCA, CAB |
Number Series
Number series use arithmetic relationships between terms. The most common possibilities to test are:
- Addition or subtraction
- Multiplication or division
- Multiplication followed by addition or subtraction
- Squares and cubes
- Prime numbers
- Consecutive differences
- Alternating terms
- Two interleaved sequences
Constant differences
Example:
14, 19, 24, 29, ?
The difference is consistently +5, so the answer is 34.
Changing differences
Example:
3, 8, 15, 24, 35, ?
The differences are:
- 8 − 3 = 5
- 15 − 8 = 7
- 24 − 15 = 9
- 35 − 24 = 11
The next difference is 13, so the answer is:
35 + 13 = 48
Mixed operations
Example:
5, 12, 26, 54, ?
The rule is:
- 5 × 2 + 2 = 12
- 12 × 2 + 2 = 26
- 26 × 2 + 2 = 54
Therefore:
54 × 2 + 2 = 110
Letter Series
Letter-series questions use the numerical positions of letters:
- A = 1
- B = 2
- C = 3
- …
- Z = 26
A useful anchor is EJOTY:
- E = 5
- J = 10
- O = 15
- T = 20
- Y = 25
You should also know opposite alphabet pairs:
- A–Z
- B–Y
- C–X
- D–W
- E–V
Example:
B, E, I, N, ?
The letter positions are 2, 5, 9, and 14. The jumps are +3, +4, and +5. The next jump is +6:
14 + 6 = 20
The 20th letter is T.
Alphanumeric Series
An alphanumeric series combines letters and numbers. Test the two components separately first, and then check whether they are related.
Example:
A1, C3, F6, J10, ?
The letters move forward by:
- A to C: +2
- C to F: +3
- F to J: +4
The next jump is +5, giving O.
The numbers are the alphabet positions of the letters:
- A = 1
- C = 3
- F = 6
- J = 10
- O = 15
Therefore, the answer is O15.
Alternating and Cyclic Series
In an alternating series, the odd-positioned terms and even-positioned terms may follow separate rules.
Example:
10, 5, 15, 10, 20, 15, 25, ?
Odd positions:
10, 15, 20, 25
Even positions:
5, 10, 15, ?
Both increase by 5, so the answer is 20.
In a cyclic series, terms repeat or rotate.
Example:
ABC, BCA, CAB, ABC, ?
The three-term cycle repeats, so the answer is BCA.
How to Solve Series Questions Quickly
Use the following sequence rather than testing random possibilities.
Step 1: Observe the rate of change
Ask whether the terms are:
- Rising slowly
- Rising rapidly
- Falling
- Alternating
- Close to squares or cubes
Slow growth usually suggests addition or subtraction. Rapid growth may indicate multiplication, powers, or a mixed operation. Treat these as starting clues, not fixed rules.
Step 2: Calculate the first differences
Subtract each term from the next.
For:
7, 11, 17, 25, 35
The differences are:
4, 6, 8, 10
The next difference is 12, so the answer is:
35 + 12 = 47
Step 3: Check second differences when necessary
If the first differences do not form an obvious pattern, calculate the differences between them.
For:
2, 5, 10, 17, 26
First differences:
3, 5, 7, 9
Second differences:
2, 2, 2
The next first difference is 11, so the next term is:
26 + 11 = 37
Step 4: Test multiplication and division
When values rise or fall quickly, calculate ratios or test rules such as:
- ×2
- ×3
- ÷2
- ×2 + 1
- ×3 − 2
Always test the rule against every available transition.
Step 5: Split alternating terms
When no single rule explains consecutive terms, separate:
- First, third, fifth, seventh terms
- Second, fourth, sixth, eighth terms
This is especially useful when the sequence moves up and down unexpectedly.
Step 6: Convert letters into positions
For a letter series, write or mentally calculate the alphabet positions. This turns the problem into a number series.
Step 7: Choose the simplest complete rule
A good rule should explain every term without unnecessary exceptions. Do not select a complicated explanation when a simpler consistent rule is available.
Step 8: Use a first-pass time limit
Because the latest published SNAP pattern averages one minute per question across the paper, a series question should not consume several minutes.
A practical first-pass approach is:
- Attempt immediately if the rule is visible.
- Spend approximately 20–30 seconds testing the most likely patterns.
- Mark the question for review if you are close but not certain.
- Skip it if the rule remains unclear.
- Return only after securing easier questions.
This is a strategy guideline, not an official per-question time limit.
Solved Series Questions for SNAP 2026
Question 1: Cube-Based Series
Find the missing term:
2, 9, 28, 65, 126, ?
Solution
Each term is one more than a consecutive cube:
- (1^3 + 1 = 2)
- (2^3 + 1 = 9)
- (3^3 + 1 = 28)
- (4^3 + 1 = 65)
- (5^3 + 1 = 126)
The next term is:
(6^3 + 1 = 216 + 1 = 217)
Answer: 217
Question 2: Alternating Series
Find the next number:
10, 5, 15, 10, 20, 15, 25, ?
Solution
Separate the odd and even positions.
Odd positions:
10, 15, 20, 25
Even positions:
5, 10, 15, ?
Both increase by 5.
Answer: 20
Question 3: Multiplication and Addition
Find the missing value:
4, 10, 22, 46, 94, ?
Solution
Each term is obtained by multiplying the preceding term by 2 and adding 2:
- 4 × 2 + 2 = 10
- 10 × 2 + 2 = 22
- 22 × 2 + 2 = 46
- 46 × 2 + 2 = 94
Therefore:
94 × 2 + 2 = 190
Answer: 190
The differences—6, 12, 24, 48, and 96—also confirm the answer, but the direct rule is faster.
Question 4: Letter Series
Find the missing letter:
A, C, F, J, O, ?
Solution
Convert the letters into positions:
1, 3, 6, 10, 15
The jumps are:
+2, +3, +4, +5
The next jump is +6:
15 + 6 = 21
The 21st letter is U.
Answer: U
Question 5: Alphanumeric Series
Find the next term:
A1, C3, F6, J10, ?
Solution
The letter jumps are +2, +3, and +4. The next jump is +5:
J + 5 = O
The numbers represent the alphabet positions of the letters:
O = 15
Answer: O15
Question 6: Increasing Difference
Find the next term:
7, 10, 16, 25, 37, ?
Solution
The differences are:
- 10 − 7 = 3
- 16 − 10 = 6
- 25 − 16 = 9
- 37 − 25 = 12
The differences increase by 3. The next difference is 15.
37 + 15 = 52
Answer: 52
Question 7: Backward Letter Series
Find the next letter:
Z, W, S, N, ?
Solution
The positions are:
26, 23, 19, 14
The backward jumps are:
−3, −4, −5
The next jump is −6:
14 − 6 = 8
The eighth letter is H.
Answer: H
Question 8: Connected Alphanumeric Pattern
Find the next term:
A2, C6, F12, J20, ?
Solution
The letter jumps are:
+2, +3, +4
The next jump is +5, giving O.
The numbers follow:
- 1 × 2 = 2
- 2 × 3 = 6
- 3 × 4 = 12
- 4 × 5 = 20
- 5 × 6 = 30
Answer: O30
Common Mistakes to Avoid
Forcing one rule on an alternating series
When consecutive differences appear irregular, split odd and even positions before testing more complicated formulas.
Stopping after checking only addition
Rapidly increasing terms often use multiplication, powers, or multiplication followed by addition.
Ignoring backward alphabet movement
Letter series do not always move from A towards Z. Check backward jumps and opposite-letter pairs.
Using a rule that does not fit every term
A pattern is not valid merely because it explains the last two transitions. Verify it across the full sequence.
Confusing first and second differences
First differences are the gaps between the original terms. Second differences are the gaps between those first differences.
Spending too long on one question
Past effort does not make a difficult question more valuable. Leave it and return later.
Guessing despite negative marking
Under the latest published official pattern, an incorrect response attracts a 25% penalty. Attempt doubtful questions only after eliminating options or establishing a defensible pattern.
What Should You Memorize?
Candidates do not need to memorize every possible sequence. The following reference points are useful:
- Squares from (1^2) to (30^2)
- Cubes from (1^3) to (15^3)
- Prime numbers at least up to 100
- Alphabet positions from A to Z
- Opposite alphabet pairs
- Common powers of 2 and 3
- Basic divisibility rules
Memorization should support pattern recognition rather than replace logical checking.
Daily Preparation Strategy
A focused 20-minute routine is more useful than occasionally solving a large untimed set.
Five minutes: revise reference values
Review:
- Squares
- Cubes
- Prime numbers
- Alphabet positions
- Opposite-letter pairs
Ten minutes: solve a timed set
Attempt approximately 8–10 mixed series questions. Include number, letter, and alphanumeric patterns rather than practising only your strongest type.
Five minutes: maintain an error log
For every incorrect or skipped question, record:
- The pattern type
- The clue you missed
- The fastest valid method
- The time spent
- The action to take next time
Do not write only the correct answer. The purpose of an error log is to improve recognition.
SNAP Series Practice Questions
Try these questions before checking the answers.
-
3, 8, 15, 24, 35, ?
-
81, 27, 9, 3, ?
-
B, E, I, N, ?
-
2, 6, 12, 20, 30, ?
-
A1, D4, H8, M13, ?
Answers and Explanations
Answer 1: B. 48
Differences:
+5, +7, +9, +11
The next difference is +13.
35 + 13 = 48
Answer 2: B. 1
Each term is divided by 3:
81 → 27 → 9 → 3 → 1
Answer 3: B. T
Letter jumps:
+3, +4, +5
The next jump is +6:
N + 6 = T
Answer 4: C. 42
The terms follow (n(n+1)):
- 1 × 2 = 2
- 2 × 3 = 6
- 3 × 4 = 12
- 4 × 5 = 20
- 5 × 6 = 30
- 6 × 7 = 42
Answer 5: B. S19
Both letters and numbers increase by:
+3, +4, +5
The next increase is +6:
- M + 6 = S
- 13 + 6 = 19
Therefore, the answer is S19.
Frequently Asked Questions
Are series questions guaranteed to appear in SNAP 2026?
No fixed topic-wise number of series questions is officially guaranteed. Series completion is a useful logical-reasoning topic, but the exact question mix may vary between tests. Check the final SNAP 2026 information and practise the complete Analytical and Logical Reasoning syllabus.
How many series questions can appear in SNAP?
The official test structure gives the total number of questions in the Analytical and Logical Reasoning section but does not publish a fixed count for series questions. Avoid basing your preparation on an assumed topic-wise weightage.
How much time should I spend on a series question?
There is no official per-question limit. As a first-pass strategy, spend about 20–30 seconds checking the most likely rules. Continue only when you are close to confirming the pattern.
What should I check first in a number series?
Check, in order:
- Simple differences
- Changing differences
- Multiplication or division
- Mixed operations
- Alternating terms
- Squares, cubes, and primes
The order may change when the terms provide an obvious clue.
Is memorizing squares and cubes necessary?
It is not mandatory, but it significantly reduces calculation time in power-based series. Squares up to 30 and cubes up to 15 are useful preparation targets.
How can I improve accuracy in letter series?
Memorize alphabet positions, use EJOTY as a five-letter anchor, practise backward movement, and learn opposite pairs such as A–Z and B–Y.
Should I guess if I cannot find the pattern?
Blind guessing is risky under a negative-marking system. Attempt the question only when you can identify the rule or eliminate enough answer choices to make the attempt reasonable.