Question

Identify the incorrect number in the following series:

• A. 55
• B. 62
• C. 76
• D. 86

Hint:

Look carefully at alternating patterns of differences to spot errors in number series.

Answer 1

The Correct Option is A

The given series is: 100, 97, 90, 86, 76, 71, 62, 55
Step 1: Check differences between consecutive terms:
\(100 - 97 = 3\)
\(97 - 90 = 7\)
\(90 - 86 = 4\)
\(86 - 76 = 10\)
\(76 - 71 = 5\)
\(71 - 62 = 9\)
\(62 - 55 = 7\)
Step 2: Observing alternate differences:
Odd differences: 3, 4, 5, 7. Clearly, the sequence should continue as 3,4,5,6..., but the last difference is incorrectly shown as 7. Thus, the correct number should be \(62 - 6 = 56\), not 55. Hence, 55 is incorrect.