Complete the sequence of odd squares: __, 9, 25, 49, 81, 121.
Aptitude
Odd Man Out and Series
Difficulty: Easy
Choose an option
-
A5
-
B1
-
C4
-
D3
-
ENone of these
Answer
Correct Answer: 1
Explanation
Introduction / Context:The sequence lists squares of consecutive odd numbers. Identifying this property lets us find the term preceding 9 (which is 3^2).
Given Data / Assumptions:
- Known terms: 9, 25, 49, 81, 121 = 3^2, 5^2, 7^2, 9^2, 11^2.
Concept / Approach:
- Preceding odd number is 1; its square is 1.
Step-by-Step Solution:
Odd numbers: 1, 3, 5, 7, 9, 11Squares: 1, 9, 25, 49, 81, 121Hence the missing initial term is 1Verification / Alternative check:Sequence strictly follows (2n−1)^2; with n = 1 gives 1, matching the missing place.
Why Other Options Are Wrong:
- 3,4,5 are not squares of an odd integer preceding 3^2 in this pattern.
- None of these: Not applicable because 1 is valid.
Common Pitfalls:
- Assuming arithmetic progression of the values instead of recognizing squared odds.
Final Answer:1