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Question

Select the correct option that will fill in the blank and complete the series.

0, 2, 3, 5, 10, 18, 33, 61, 112, _________

The correct answer is

206

Solving the Number Series Puzzle

The question asks us to identify the pattern in the given number series and find the next term. The series is: 0, 2, 3, 5, 10, 18, 33, 61, 112, _________

Analyzing the Number Series Pattern

Let's look at the relationship between consecutive terms or groups of terms to discover the underlying rule governing this series. We can try different common patterns like arithmetic progression, geometric progression, differences, or sum of previous terms.

Let's denote the terms of the series as $T_1, T_2, T_3, \dots$.

  • $T_1 = 0$
  • $T_2 = 2$
  • $T_3 = 3$
  • $T_4 = 5$
  • $T_5 = 10$
  • $T_6 = 18$
  • $T_7 = 33$
  • $T_8 = 61$
  • $T_9 = 112$
  • $T_{10} = ?$

Let's examine if a term is the sum of the previous terms:

  • $T_4 = 5$. Can this be related to $T_1, T_2, T_3$? $T_1+T_2+T_3 = 0+2+3 = 5$. This fits $T_4$.
  • $T_5 = 10$. Can this be related to $T_2, T_3, T_4$? $T_2+T_3+T_4 = 2+3+5 = 10$. This fits $T_5$.
  • $T_6 = 18$. Can this be related to $T_3, T_4, T_5$? $T_3+T_4+T_5 = 3+5+10 = 18$. This fits $T_6$.

The pattern seems to be that, from the fourth term onwards, each term is the sum of the three preceding terms.

The recursive formula for the series, for $n \ge 4$, is $T_n = T_{n-1} + T_{n-2} + T_{n-3}$.

Applying the Pattern to Find the Next Term

We need to find $T_{10}$. According to the identified pattern, $T_{10}$ will be the sum of the three preceding terms: $T_7, T_8,$ and $T_9$.

  • $T_7 = 33$
  • $T_8 = 61$
  • $T_9 = 112$

So, $T_{10} = T_7 + T_8 + T_9$.

Let's calculate the sum:

$T_{10} = 33 + 61 + 112$

$T_{10} = 94 + 112$

$T_{10} = 206$

Summary of the Series Pattern

The first three terms (0, 2, 3) serve as the initial values. Starting from the fourth term, each term is the sum of the previous three terms.

Term Number (n) Term ($T_n$) Pattern Calculation ($T_{n-1} + T_{n-2} + T_{n-3}$ for $n \ge 4$)
1 0 Initial term
2 2 Initial term
3 3 Initial term
4 5 $T_1 + T_2 + T_3 = 0 + 2 + 3 = 5$
5 10 $T_2 + T_3 + T_4 = 2 + 3 + 5 = 10$
6 18 $T_3 + T_4 + T_5 = 3 + 5 + 10 = 18$
7 33 $T_4 + T_5 + T_6 = 5 + 10 + 18 = 33$
8 61 $T_5 + T_6 + T_7 = 10 + 18 + 33 = 61$
9 112 $T_6 + T_7 + T_8 = 18 + 33 + 61 = 112$
10 ? $T_7 + T_8 + T_9 = 33 + 61 + 112 = 206$

The next term in the series is 206.

Revision Table: Number Series Concepts

Concept Description Example Pattern
Arithmetic Series Each term is obtained by adding a constant difference to the previous term. 2, 5, 8, 11, ... (Difference is 3)
Geometric Series Each term is obtained by multiplying the previous term by a constant ratio. 3, 6, 12, 24, ... (Ratio is 2)
Difference Series The differences between consecutive terms follow a pattern (arithmetic, geometric, etc.). 1, 4, 9, 16, ... (Differences are 3, 5, 7 - an arithmetic series)
Fibonacci-like Series Each term is the sum of the one or two previous terms (or a variation). The given series is a variation where each term is the sum of the three previous terms. 1, 1, 2, 3, 5, 8, ... (Standard Fibonacci: $T_n = T_{n-1} + T_{n-2}$)

Additional Information: Identifying Series Patterns

Identifying the pattern in a number series is a common type of question in logical reasoning and quantitative aptitude tests. Here are some general strategies:

  • Look at Differences: Calculate the difference between consecutive terms. If the first differences don't show a pattern, calculate the differences of the differences (second differences), and so on.
  • Look at Ratios: Calculate the ratio between consecutive terms to check for geometric progression.
  • Look for Sums/Products of Previous Terms: Check if a term is the sum or product of one or more previous terms (like Fibonacci or the pattern in this question).
  • Look for Squares, Cubes, or Other Powers: The terms might be related to squares, cubes, or other powers of numbers, possibly with an addition or subtraction. (e.g., $n^2$, $n^2+1$, $n^3-1$).
  • Look for Alternating Patterns: Sometimes two different patterns alternate within the same series.
  • Look for Combinations: The pattern might involve a combination of operations (e.g., multiply by 2 and add 1).

Practice with various types of series helps in quickly recognizing 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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