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Which of the following numbers will replace the question mark (?) in the given series?4, 7, 17, 38, 72, 123, 193, 286, 408, ?

  1. A
    521
  2. B
    561
  3. C
    512
  4. D
    516

Solution & Step-by-step Explanation

Let's find the difference between consecutive terms in the series: Now let's compute the second-level differences (differences of differences): Notice that the second-level differences are consecutive prime numbers: .The next prime number after is .Therefore:Next first-level difference = Missing number =

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Try it yourself before checking the explanation above.

Which of the following numbers will replace the question mark (?) in the given series?4, 7, 17, 38, 72, 123, 193, 286, 408, ?
A
521
B
561
C
512
D
516

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