Number series — find the next two terms of the sequence: 84, 78, 72, 66, 60, 54, 48
Verbal Reasoning
Number Series
Difficulty: Easy
Choose an option
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A44 34
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B42 36
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C42 32
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D40 34
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E38 32
Answer
Correct Answer: 42 36
Explanation
Introduction / Context:This is a decreasing arithmetic progression, common in test questions. Recognizing the constant negative step enables quick extrapolation to the next terms without complicated calculations.
Given Data / Assumptions:
- Sequence: 84, 78, 72, 66, 60, 54, 48
- We need the next two values (positions 8 and 9).
Concept / Approach:Find the common difference d by subtracting consecutive terms. For a descending AP, d will be negative, and we keep subtracting d to extend the series.
Step-by-Step Solution:
Common difference: 78 − 84 = −6 (constant across the list).Next term: 48 − 6 = 42.Term after that: 42 − 6 = 36.Therefore, the next two terms are 42 and 36.Verification / Alternative check:
Mid-sequence confirmation: 66 − 6 = 60 and 60 − 6 = 54, consistent with d = −6.Why Other Options Are Wrong:
44 34 / 42 32 / 40 34 / 38 32: These pairs deviate from the constant −6 step for one or both entries.Common Pitfalls:
Switching to variable steps unnecessarily; the pattern is uniformly −6.Final Answer:42 36