Multiple choice

Find the wrong number in following number series. 854 , 886 , 923 , 964 , 1007 , 1054 , 1107

  1. 923

  2. 1007

  3. 854

  4. 1054

  5. 1107
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Differences: 886-854=32, 923-886=37, 964-923=41, 1007-964=43, 1054-1007=47, 1107-1054=53. The differences are primes: 31, 37, 41, 43, 47, 53. 886-31=855, not 854. If the series started at 855, the differences would be 31, 37, 41, 43, 47, 53. Thus 854 is the wrong number.

AI explanation

The differences between consecutive terms increase by 6, then 4, then 5, and so on. The first difference should be 32, which makes the first term 854; the second difference is 37, which makes the second term 891; the third difference is 41, making the third term 932. The pattern of differences is 37, 41, 43, 47, 53 and 59, which are consecutive prime numbers; subtracting 37 from 886 gives 849, which is the correct first term. The wrong number is 854.

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