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Question

Find the missing term in the following series. 
361, 289, 169, ____, 49

The correct answer is
121

Series Missing Term Identification

The question asks to identify the missing term in the numerical series: 361, 289, 169, ____, 49.

Analyzing the Series Pattern

  • Observe the given numbers: 361, 289, 169, 49.
  • Recognize that these numbers are perfect squares.
  • Calculate the square roots of the known terms:
    • $\sqrt{361} = 19$
    • $\sqrt{289} = 17$
    • $\sqrt{169} = 13$
    • $\sqrt{49} = 7$
  • Examine the sequence of the square roots: 19, 17, 13, ?, 7.
  • Notice that these roots are prime numbers in descending order.
  • The sequence of prime numbers is 19, 17, 13, 11, 7.
  • The missing prime number in the sequence is 11.

Calculating the Missing Term

The missing term in the original series corresponds to the square of the missing prime root (11).

  • Calculate the square of 11: $11^2 = 121$.

Therefore, the missing term in the series is 121.

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Important Questions from Number Series

  1. Select the number from among the given options that can replace the question mark (?) in the following series.

    37, 52, 74, 104, 143, ?

  2. Select the number that can replace the question mark (?) in the following series.

    17, 19, 22, 27, 34, 45, 58,?
  3. Select the number from among the given options that can replace the question mark (?) in the following series.

    10, 14, 31, 35, 73, 77, ?

  4. Select the number from among the given options that can replace the question mark (?) in the following series.

    215, 231, 256, 292, ?

  5. Select the number from among the given options that can replace the question mark (?) in the following series.

    6, 6, 8, 24, 28, 140, ?

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