Find the next term in the sequence: 12, 15, 21, 30, 42, 57, __.
Aptitude
Odd Man Out and Series
Difficulty: Easy
Choose an option
-
A59
-
B63
-
C65
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D75
-
ENone of these
Answer
Correct Answer: 75
Explanation
Introduction / Context:We determine the rule generating the sequence. The increments between consecutive terms are increasing by a constant amount, a common pattern in aptitude tests.
Given Data / Assumptions:
- Sequence: 12, 15, 21, 30, 42, 57, __.
Concept / Approach:
- Compute consecutive differences and look for a simple pattern (e.g., +3, +6, +9 …).
Step-by-Step Solution:
15−12 = 321−15 = 630−21 = 942−30 = 1257−42 = 15Pattern: differences increase by +3 each time ⇒ next difference = 18Next term = 57 + 18 = 75Verification / Alternative check:Continuing the +3 step keeps the structure consistent; 75 fits naturally as the next term.
Why Other Options Are Wrong:
- 59, 63, 65: Do not match the +3 ladder of differences.
- None of these: Not applicable; 75 is correct.
Common Pitfalls:
- Assuming constant difference or ratio instead of a second-level arithmetic pattern.
Final Answer:75