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Sequential or Series-Based Analogy

Introduction

Sequential or Series-Based Analogies test your ability to identify logical patterns across a set of numbers, letters, or mixed elements. Unlike simple arithmetic analogies, these questions involve recognizing and applying the same progression rule in two or more sequences.

Pattern: Sequential or Series-Based Analogy

Pattern

The key concept is: both pairs or series follow the same progression or pattern rule - such as arithmetic, geometric, alphabetical, or alternating logic.

Step-by-Step Example

Question

2, 4, 6 : 3, 6, 9 :: 5, 10, 15 : ______
(A) 6, 12, 18 (B) 7, 14, 21 (C) 8, 16, 24 (D) 9, 18, 27

Solution

  1. Step 1: Identify structure of the first pair.

    Series1a = 2, 4, 6 → start = 2, common difference = +2.
    Series1b = 3, 6, 9 → start = 3, common difference = +3.

  2. Step 2: Infer the transformation between the first pair.

    The starting term increases by +1 (2 → 3) and the common difference increases by +1 (+2 → +3).

  3. Step 3: Apply same transformation to the second pair.

    Series2a = 5, 10, 15 → start = 5, diff = +5. Apply start +1 → 6; diff +1 → +6.

  4. Final Answer:

    6, 12, 18 → Option A

  5. Quick Check:

    Series2b with start = 6 and diff = +6 gives 6, 12, 18 and mirrors the same structural change as the first pair ✅

Quick Variations

1. Numeric series with arithmetic or geometric patterns.

2. Letter series with positional shifts (e.g., A, C, E → B, D, F).

3. Mixed logic (e.g., number + letter pattern, alternate arithmetic rules).

4. Increment-Decrement alternating series.

5. Reverse or mirror sequence progressions.

Trick to Always Use

  • Step 1 → Identify if the series is numerical, alphabetical, or mixed.
  • Step 2 → Determine the exact rule (+, -, ×, ÷, or positional jump).
  • Step 3 → Apply the same pattern consistently to the missing series.
  • Step 4 → Verify that every term follows identical spacing or patterning.

Summary

Summary

  • Sequential analogies compare two or more ordered series, not single values.
  • Find the consistent rule for starting term and difference or ratio in the first pair.
  • Apply the same transformation pattern to generate the missing sequence.
  • Verify that both pairs maintain identical spacing and logic consistency.

Example to remember:
2, 4, 6 : 3, 6, 9 :: 5, 10, 15 : 6, 12, 18

Practice

(1/5)
1. 3, 6, 9 : 4, 8, 12 :: 5, 10, 15 : ______
easy
A. 6, 12, 18
B. 7, 14, 21
C. 8, 16, 24
D. 9, 18, 27

Solution

  1. Step 1: Identify pattern:

    Series1a = 3, 6, 9 → start = 3, diff = +3; Series1b = 4, 8, 12 → start = 4, diff = +4.

  2. Step 2: Apply rule:

    The rule is start +1 and diff +1.

  3. Step 3: Compute new series:

    Series2a = 5, 10, 15 → start = 5, diff = +5 → apply start +1 = 6; diff +1 = +6 → 6, 12, 18.

  4. Final Answer:

    6, 12, 18 → Option A

  5. Quick Check:

    Same structural rule (Start +1, Diff +1) holds ✅
Hint: When both sequences are arithmetic, compare the first term and difference.
Common Mistakes: Confusing common difference with a multiplication rule.
2. A, C, E : B, D, F :: P, R, T : ______
easy
A. Q, S, U
B. O, Q, S
C. R, T, V
D. S, U, W

Solution

  1. Step 1: Identify pattern:

    A, C, E → alternate letters (+2 jump each). B, D, F → same pattern, starting one ahead.

  2. Step 2: Apply rule:

    P, R, T → +2 pattern, so start one ahead (Q) and continue same +2 pattern → Q, S, U.

  3. Final Answer:

    Q, S, U → Option A

  4. Quick Check:

    A→B (+1 start), same pattern applied ✅
Hint: For alphabetic series, note the skip count between letters.
Common Mistakes: Starting from wrong letter or using wrong letter gap.
3. 1, 3, 5, 7 : 2, 4, 6, 8 :: 10, 12, 14, 16 : ______
easy
A. 11, 13, 15, 17
B. 12, 14, 16, 18
C. 13, 15, 17, 19
D. 9, 11, 13, 15

Solution

  1. Step 1: Identify pattern:

    1,3,5,7 (odd numbers) → 2,4,6,8 (even numbers next to each).

  2. Step 2: Apply rule:

    10,12,14,16 (even numbers) → add +1 to each to get next odd sequence.

  3. Step 3: Compute new series:

    10 +1 = 11, 12 +1 = 13, 14 +1 = 15, 16 +1 = 17 → 11,13,15,17.

  4. Final Answer:

    11, 13, 15, 17 → Option A

  5. Quick Check:

    Even → next odd pattern applied ✅
Hint: When one series converts odd to even, apply the same parity logic.
Common Mistakes: Adding +2 instead of +1 to each term.
4. 5, 10, 20 : 10, 20, 40 :: 7, 14, 28 : ______
medium
A. 8, 16, 32
B. 9, 18, 36
C. 14, 28, 56
D. 15, 30, 60

Solution

  1. Step 1: Identify pattern:

    First pair: each term doubles (×2 rule). 5→10→20 and 10→20→40 both follow ×2.

  2. Step 2: Apply rule:

    Apply same logic to 7,14,28; next sequence must double.

  3. Step 3: Compute new series:

    7×2 = 14, 14×2 = 28, 28×2 = 56 → 14,28,56.

  4. Final Answer:

    14, 28, 56 → Option C

  5. Quick Check:

    ×2 rule holds consistently ✅
Hint: Look for consistent multiplication ratios in geometric progressions.
Common Mistakes: Adding instead of multiplying.
5. 2, 5, 10 : 5, 10, 17 :: 3, 8, 15 : ______
medium
A. 6, 13, 22
B. 8, 15, 24
C. 7, 14, 23
D. 9, 16, 25

Solution

  1. Step 1: Identify the pattern in the first pair

    First series: 2, 5, 10 → differences are +3, +5. Next series: 5, 10, 17 → differences are +5, +7. The pattern shows each new series starts from the second term of the previous series, and the internal differences increase by +2 each time (+3 → +5 → +7).

  2. Step 2: Apply the same rule to the second pair

    Second given series: 3, 8, 15 → differences are +5, +7. Following the same logic, the next series will start from the 2nd term (8), then 3rd term (15), and the next term should be 15 + 9 = 24.

  3. Step 3: Construct the new sequence

    Therefore, the new sequence is 8, 15, 24.

  4. Final Answer:

    8, 15, 24 → Option B

  5. Quick Check:

    Each new series continues from the previous one, maintaining +2 growth in internal differences ✅
Hint: Notice that each new series begins with the middle term of the previous one and continues with growing odd-number differences (+3, +5, +7, +9).
Common Mistakes: Treating the series as a simple arithmetic progression instead of recognizing the overlapping and increasing-difference pattern.

Mock Test

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