All Exams Test series for 1 year @ ₹349 only
Question

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

205, 222, 241, 264, 293, ?

The correct answer is

324

Solving the Number Series Pattern

The question asks us to find the next number in the given series: 205, 222, 241, 264, 293, ?

To solve a number series problem, we first look for a pattern, usually by finding the difference between consecutive terms.

Step 1: Calculate the Differences Between Consecutive Terms

Let's find the difference between each adjacent pair of numbers in the series:

  • Difference between 222 and 205: \(222 - 205 = 17\)
  • Difference between 241 and 222: \(241 - 222 = 19\)
  • Difference between 264 and 241: \(264 - 241 = 23\)
  • Difference between 293 and 264: \(293 - 264 = 29\)

The sequence of differences is thus: 17, 19, 23, 29.

Step 2: Identify the Pattern in the Differences

Let's examine the sequence of differences: 17, 19, 23, 29. We need to find the pattern in this new sequence.

Observe that these numbers (17, 19, 23, 29) are prime numbers. A prime number is a natural number greater than 1 that is not a product of two smaller natural numbers.

The sequence 17, 19, 23, 29 is a sequence of prime numbers in increasing order. The next prime number after 29 is 31.

Step 3: Determine the Next Difference in the Series

Following the pattern, the next difference to be added to the last term of the original series (293) should be the next prime number after 29, which is 31.

Step 4: Calculate the Next Term in the Series

To find the next term in the original series, we add the next difference (31) to the last term (293):

\(293 + 31 = 324\)

Conclusion

The next number in the series 205, 222, 241, 264, 293, ? is 324.

The series progresses by adding consecutive prime numbers starting from 17.

Term Value Difference from Previous Term Pattern (Prime Number)
1st 205 - -
2nd 222 \(222 - 205 = 17\) 17 (Prime)
3rd 241 \(241 - 222 = 19\) 19 (Prime)
4th 264 \(264 - 241 = 23\) 23 (Prime)
5th 293 \(293 - 264 = 29\) 29 (Prime)
6th ? \(293 + 31 = 324\) 31 (Next Prime)

Revision Table: Key Concepts for Number Series

Concept Explanation Example Pattern
Arithmetic Series Adding/Subtracting a constant value. 2, 4, 6, 8... (Add 2)
Geometric Series Multiplying/Dividing by a constant value. 2, 4, 8, 16... (Multiply by 2)
Difference Series The differences between terms form a pattern (arithmetic, geometric, prime, squares, cubes, etc.). 1, 2, 4, 7, 11... (Differences: 1, 2, 3, 4...)
Double Difference Series The differences of the differences form a pattern. See the problem solved above (2, 4, 6... in second differences).
Prime Number Series Adding consecutive prime numbers. 1, 3, 6, 11, 18... (Add 2, 3, 5, 7...)
Square/Cube Series Adding squares or cubes of natural numbers. 2, 6, 15, 31... (Add \(2^2-1\), \(3^2\)-0, \(4^2\)-1... or other logic)

Additional Information: Understanding Prime Numbers in Patterns

Prime numbers are fundamental in number theory and frequently appear in logical reasoning and number series questions. Recognizing the sequence of prime numbers is crucial for solving such problems quickly.

  • The sequence of prime numbers starts with 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, and so on.
  • In this specific problem, the differences between the terms formed a sequence of prime numbers starting from 17.
  • When you see differences that don't form a simple arithmetic or geometric sequence, consider patterns like prime numbers, squares (\(n^2\)), cubes (\(n^3\)), or Fibonacci-like sequences.
  • Practice identifying common number sequences like primes, squares, and cubes to improve your speed in finding patterns.
Was this answer helpful?

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, ?

Need Expert Advice?

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App