Join 60,000+ competitive exam aspirants
or with email
Your Cart
Subtotal₹0
Total₹0
Examoogle • User • info@examoogle.com • EE-2024-8821
Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked
Join 60,000+ competitive exam aspirants
What should come in place of the question mark (?) in the following series? 121, 108, 97, 88, 81, ?
74
76
78
72
76
Subtract consecutive odd numbers descending by 2 (13, 11, 9, 7). Next difference is 5, so 81 - 5 = 76.
Subtract consecutive odd numbers descending by 2 (13, 11, 9, 7). Next difference is 5, so 81 - 5 = 76.
Step 1: Find 1st differences
121 - 108 = 13, 108 - 97 = 11, 97 - 88 = 9, 88 - 81 = 7.
Step 2: Identify sub-pattern
Differences decrease by 2 each time (13 → 11 → 9 → 7).
Step 3: Compute next term
Next difference = 7 - 2 = 5. Result = 81 - 5 = 76.
A: 74 is derived from subtracting 7, C: 78 breaks the pattern sequence, D: 72 repeats the 9 difference.
B is correct because consecutive terms decrease by descending odd numbers (13, 11, 9, 7), meaning the next decrease is 5, giving 81 - 5 = 76.
Always verify second-level differences if first-level differences form an arithmetic progression.
Get instant step-by-step AI explanations, full shift Previous Year Papers (SSC GD, RRB, SSC JE), and regional rank analysis on the official Examoogle App.
Free Download • 100K+ Aspirants