Finding the Missing Number in a Logical Series

The question presents a number series and asks us to find the missing term. The given series is:

8, 11, 14, 17, 20, ?

To solve this, we need to analyze the series and find the pattern that connects the numbers.

Identifying the Pattern

Let's look at the difference between consecutive terms in the series:

• From 8 to 11: The difference is $11 - 8 = 3$.
• From 11 to 14: The difference is $14 - 11 = 3$.
• From 14 to 17: The difference is $17 - 14 = 3$.
• From 17 to 20: The difference is $20 - 17 = 3$.

We can clearly see a consistent pattern: each term is obtained by adding 3 to the previous term. This is an arithmetic progression with a common difference of 3.

Calculating the Missing Term

Following the identified pattern, the missing number will be the result of adding 3 to the last given term, which is 20.

Missing Number = Last term + Common difference

Missing Number $= 20 + 3$

Missing Number $= 23$

Conclusion

Based on the arithmetic pattern where 3 is added to each preceding number, the next number in the series 8, 11, 14, 17, 20, ? is 23.

Revision Table: Analyzing the Number Pattern

Additional Information: Understanding Number Series

Number series problems are common in reasoning and quantitative aptitude tests. They assess your ability to identify patterns and rules governing a sequence of numbers. Common patterns include:

• Arithmetic progression (constant difference)
• Geometric progression (constant ratio)
• Difference series (pattern in the differences between terms)
• Alternating series (two different patterns alternating)
• Series based on squares, cubes, or other powers
• Fibonacci series (sum of previous two terms)

Practice with various types of series helps in quickly recognizing the underlying pattern.