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Question

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

26, 36, 30, 40, 34, 44, ?

The correct answer is

38

Finding the Pattern in a Number Series

Let's examine the given number series to identify the underlying pattern. The series is: 26, 36, 30, 40, 34, 44, ?

We need to determine the number that replaces the question mark by figuring out how the numbers are changing from one term to the next.

Analyzing the Number Series Pattern

Let's look at the differences or relationships between consecutive terms:

  • From 26 to 36: $36 - 26 = +10$
  • From 36 to 30: $30 - 36 = -6$
  • From 30 to 40: $40 - 30 = +10$
  • From 40 to 34: $34 - 40 = -6$
  • From 34 to 44: $44 - 34 = +10$

Based on this analysis, we can see a clear alternating pattern:

  • Add 10 to the first term to get the second term.
  • Subtract 6 from the second term to get the third term.
  • Add 10 to the third term to get the fourth term.
  • Subtract 6 from the fourth term to get the fifth term.
  • Add 10 to the fifth term to get the sixth term.

The pattern is consistently adding 10, then subtracting 6, and repeating this sequence ($+10, -6, +10, -6, +10, \ldots$).

Applying the Pattern to Find the Next Number

The last number given in the series is 44. Following the established pattern, the next operation after adding 10 should be subtracting 6.

So, to find the number that replaces the question mark, we apply the next step in the pattern to the last number (44):

$44 - 6 = 38$

Therefore, the number that replaces the question mark is 38.

Verification of the Series Pattern

The series with the found number is: 26, 36, 30, 40, 34, 44, 38.

Let's check the steps:

  • $26 + 10 = 36$
  • $36 - 6 = 30$
  • $30 + 10 = 40$
  • $40 - 6 = 34$
  • $34 + 10 = 44$
  • $44 - 6 = 38$

The pattern holds true for the entire series.

Conclusion on the Number Series

The number that should replace the question mark in the series 26, 36, 30, 40, 34, 44, ? is 38.

Term Number Operation to Next Term
1st 26 $+10$
2nd 36 $-6$
3rd 30 $+10$
4th 40 $-6$
5th 34 $+10$
6th 44 $-6$
7th 38

Revision Table: Understanding Number Series

Concept Description Example Pattern
Arithmetic Series Each term is found by adding a constant difference to the previous term. 2, 5, 8, 11, ... (difference = 3)
Geometric Series Each term is found by multiplying the previous term by a constant ratio. 3, 6, 12, 24, ... (ratio = 2)
Alternating Series The pattern involves operations that alternate between different types (like + then -, or + then *). Used in this problem: +10, -6, +10, -6, ...
Difference Method Calculating the differences between consecutive terms to find a pattern. Useful for identifying arithmetic progressions or patterns in differences.

Additional Information: Solving Number Series Questions

Solving number series questions often involves looking for simple arithmetic operations (addition, subtraction, multiplication, division), or combinations of these, applied consistently between terms. Sometimes the pattern might involve squares, cubes, prime numbers, or multiple interleaved series.

  • Look for differences: Calculate the difference between consecutive terms. If the differences are constant, it's an arithmetic series. If the differences themselves form a pattern, analyze that pattern.
  • Look for ratios: Calculate the ratio between consecutive terms. If the ratio is constant, it's a geometric series.
  • Check for alternating patterns: The operation might change from one step to the next, as seen in this problem (+10, -6).
  • Consider multiple series: Sometimes, two separate series might be interleaved within one sequence.
  • Look for squares, cubes, or other mathematical properties: Terms might be related to squares ($1^2, 2^2, 3^2, \ldots$) or cubes ($1^3, 2^3, 3^3, \ldots$), or be prime numbers, etc.

Practicing with different types of number series helps in quickly identifying the pattern.

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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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