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Question

What should come in place of X in the given series?

22 31 49 76 112 X

The correct answer is

157

Solving the Number Series Pattern

Let's analyze the given number series: 22, 31, 49, 76, 112, X.

To find the value of X, we need to identify the pattern or rule governing the series. A common method for such series is to look at the differences between consecutive terms.

Step-by-Step Analysis of Differences

Let's calculate the difference between each term and its preceding term:

  • Difference between 31 and 22: $31 - 22 = 9$
  • Difference between 49 and 31: $49 - 31 = 18$
  • Difference between 76 and 49: $76 - 49 = 27$
  • Difference between 112 and 76: $112 - 76 = 36$

Let's list these differences:

9, 18, 27, 36

Identifying the Pattern in Differences

Now, let's look at the pattern in these differences:

  • The first difference is 9 ($9 \times 1$).
  • The second difference is 18 ($9 \times 2$).
  • The third difference is 27 ($9 \times 3$).
  • The fourth difference is 36 ($9 \times 4$).

The differences form an arithmetic progression where each term is a multiple of 9, increasing sequentially ($9n$ where $n=1, 2, 3, 4, \dots$).

Calculating the Next Term

Following this pattern, the next difference in the series should be the fifth multiple of 9, which is $9 \times 5 = 45$.

The next term in the original series (X) is obtained by adding this next difference (45) to the last known term (112).

So, $X = 112 + 45$

$X = 157$

Thus, the missing number in the series is 157.

Summary of Series and Differences
Term Value Difference from Previous Term
1st 22 -
2nd 31 $31 - 22 = 9$
3rd 49 $49 - 31 = 18$
4th 76 $76 - 49 = 27$
5th 112 $112 - 76 = 36$
6th (X) 157 $157 - 112 = 45$

Final Answer Derivation

The series is constructed by adding increasing multiples of 9 to the previous term:

  • $22 + 9 = 31$
  • $31 + 18 = 49$
  • $49 + 27 = 76$
  • $76 + 36 = 112$
  • $112 + 45 = 157$

Therefore, X = 157.

Revision Table - Number Series Analysis

Reviewing Number Series Patterns
Concept Description
Number Series A sequence of numbers that follow a particular pattern.
Difference Method Calculating the difference between consecutive terms to find a pattern.
Arithmetic Progression A sequence where the difference between consecutive terms is constant.
Series Pattern Types Common types include arithmetic, geometric, squares, cubes, alternating patterns, and difference series.

Additional Information - Understanding Number Patterns

Number series questions are common in competitive exams to test logical reasoning and pattern recognition skills. Identifying the rule requires careful observation and sometimes applying multiple layers of difference calculations if the first level of differences doesn't reveal a simple pattern.

Some common patterns include:

  • Arithmetic Series: Adding or subtracting a constant number.
  • Geometric Series: Multiplying or dividing by a constant number.
  • Square or Cube Series: Terms are squares or cubes of natural numbers, or related to them.
  • Alternating Series: Two different patterns applied alternately.
  • Difference Series: The differences between terms follow their own identifiable pattern (like the one in this problem, where the differences formed an arithmetic series).
  • Fibonacci-like Series: Each term is the sum of the two preceding terms.

Practicing different types of number series problems helps in quickly identifying the underlying 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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