Understanding the Number Series Pattern

The question asks us to find the missing number in the series: 17, 19, 22, 24, 27, ?

To solve this, we need to look at the difference between consecutive terms in the series and identify a pattern.

Analyzing the Differences Between Terms

Let's calculate the difference between each adjacent pair of numbers:

• Difference between the 2nd and 1st term: $19 - 17 = 2$
• Difference between the 3rd and 2nd term: $22 - 19 = 3$
• Difference between the 4th and 3rd term: $24 - 22 = 2$
• Difference between the 5th and 4th term: $27 - 24 = 3$

Identifying the Pattern

Looking at the differences, we see a clear pattern:

The differences alternate between +2 and +3.

The sequence of differences is +2, +3, +2, +3, ...

Applying the Pattern to Find the Missing Number

Following this pattern, the next difference in the series should be +2.

So, the missing number will be the last given number plus the next difference:

Missing number = Last term + Next difference

Missing number = $27 + 2$

Missing number = $29$

Verifying the Solution

The series with the missing number filled in would be: 17, 19, 22, 24, 27, 29.

Let's check the differences:

• 19 - 17 = 2
• 22 - 19 = 3
• 24 - 22 = 2
• 27 - 24 = 3
• 29 - 27 = 2

The pattern +2, +3, +2, +3, +2 is consistent with the pattern we identified.

Conclusion

Based on the pattern analysis, the missing number in the series 17, 19, 22, 24, 27, ? is 29.

Therefore, the missing number is 29.

Revision Table: Number Series Concepts

Additional Information: Solving Number Series Questions

Solving number series questions often involves looking for patterns. Here are some common types of patterns to look for:

• Constant Difference: Each term is obtained by adding or subtracting the same number from the previous term.
• Constant Ratio: Each term is obtained by multiplying or dividing the previous term by the same number.
• Increasing or Decreasing Difference/Ratio: The difference or ratio between terms follows its own pattern (e.g., differences increase by 1 each time: +1, +2, +3, ...).
• Alternating Patterns: As seen in this question, the operation or the value of the difference/ratio alternates between two or more values.
• Squares, Cubes, or their combinations: Terms might be squares ($1^2, 2^2, 3^2, ...$) or cubes ($1^3, 2^3, 3^3, ...$), or related to them (e.g., $n^2+1$).
• Fibonacci-like Series: Each term is the sum of the previous two terms (e.g., 1, 1, 2, 3, 5, 8...).
• Combined Operations: A pattern might involve both addition/subtraction and multiplication/division, or a combination of operations for each step.

It's useful to calculate the differences between consecutive terms first, as this often reveals the pattern quickly, especially for arithmetic series or series with patterns in their differences.