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Question

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

88, 94, 106, ?, 148, 178

The correct answer is

124

Solving the Number Series Puzzle

The question asks us to find the missing number in the given series: 88, 94, 106, ?, 148, 178.

To find the missing number in a number series, we need to identify the pattern or rule that connects the terms in the sequence. Let's look at the differences between consecutive terms in the given number series.

Analyzing the Number Series Pattern

We calculate the difference between each pair of adjacent numbers:

  • Difference between the second and first term: $94 - 88 = 6$
  • Difference between the third and second term: $106 - 94 = 12$
  • Difference between the last and second-to-last term: $178 - 148 = 30$

The differences we have found so far are 6, 12, and 30. Let's list the differences:

Series: 88, 94,   106,   ?,   148,   178

Differences:       6,     12,     x,     y,     30

Where x is the difference between the missing term and 106, and y is the difference between 148 and the missing term.

Now, let's look at the differences between these differences:

  • Difference between the second difference and the first difference: $12 - 6 = 6$

This suggests a pattern where the difference between consecutive terms is increasing by a constant value. In this case, the increase appears to be 6.

Step-by-Step Solution to Find the Missing Number

Assuming the pattern of differences increasing by 6 continues:

  • The first difference is 6.
  • The second difference is 12 ($6 + 6$).
  • The third difference should be $12 + 6 = 18$.
  • The fourth difference should be $18 + 6 = 24$.
  • The fifth difference should be $24 + 6 = 30$.

This sequence of differences (6, 12, 18, 24, 30) matches the last difference we calculated (30), confirming the pattern.

Now, we use these differences to find the missing term:

  • The second term is the first term plus the first difference: $88 + 6 = 94$ (Correct)
  • The third term is the second term plus the second difference: $94 + 12 = 106$ (Correct)
  • The fourth term (the missing number) is the third term plus the third difference: $106 + 18 = 124$

So, the missing number is 124.

Verification of the Number Series

Let's insert 124 into the series and check if the pattern holds for the subsequent terms:

The series is now: 88, 94, 106, 124, 148, 178

Let's check the differences:

  • $94 - 88 = 6$
  • $106 - 94 = 12$
  • $124 - 106 = 18$
  • $148 - 124 = 24$
  • $178 - 148 = 30$

The differences are 6, 12, 18, 24, 30. The difference between these differences is consistently 6 ($12-6=6$, $18-12=6$, $24-18=6$, $30-24=6$). The pattern is correct.

Conclusion: The Missing Number

Based on our analysis of the number series pattern, the number that replaces the question mark is 124.

Revision Table: Number Series Analysis

Term Number Term Value Difference from Previous Term Difference of Differences
1 88 - -
2 94 $94 - 88 = 6$ -
3 106 $106 - 94 = 12$ $12 - 6 = 6$
4 (?) 124 $124 - 106 = 18$ $18 - 12 = 6$
5 148 $148 - 124 = 24$ $24 - 18 = 6$
6 178 $178 - 148 = 30$ $30 - 24 = 6$

Additional Information on Number Series and Patterns

Number series questions are common in logical reasoning and quantitative aptitude tests. They assess your ability to identify patterns in sequences of numbers.

Common types of number series patterns include:

  • Arithmetic Series: A constant difference between consecutive terms.
  • Geometric Series: A constant ratio between consecutive terms.
  • Difference Series: The differences between consecutive terms form their own identifiable pattern (as seen in this problem). This can be a simple arithmetic series or another type of sequence.
  • Double Difference Series: The differences between the differences have a pattern (as in this case, a constant difference).
  • Squares or Cubes Series: Terms are squares or cubes of numbers, possibly with additions or subtractions.
  • Fibonacci Series: Each term is the sum of the two preceding terms.
  • Alternating Series: Two different patterns alternate within the same series.

Solving number series problems often involves calculating differences, ratios, or looking for other mathematical operations (addition, subtraction, multiplication, division, squares, cubes) between terms or their positions in the sequence.

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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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