Find the wrong number in the series 121, 169, 289, 400, 529
2026
Find the wrong number in the series
121, 169, 289, 400, 529
Answer: C. 400 — Look for a common rule among the numbers. 121 = 11², and 11 is prime. 169 = 13², and 13 is prime. 289 = 17², and 17 is prime. 400 = 20², but 20 is not prime.…
- A.
121
- B.
289
- C.
400
- D.
529
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Show answer & explanation
Correct answer: C
Look for a common rule among the numbers.
121 = 11², and 11 is prime.
169 = 13², and 13 is prime.
289 = 17², and 17 is prime.
400 = 20², but 20 is not prime.
529 = 23², and 23 is prime.
So all numbers except 400 are perfect squares of prime numbers. Therefore, 400 is the wrong number in the series.
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