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Question

Select the set in which the numbers are related in the same way as are the numbers of the given sets.

(NOTE : Operations should be performed on the whole numbers, without breaking down the numbers into its constituent digits. E.g. 13 - Operations on 13 such as adding /subtracting /multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.)

(16, 22, 28)

(14, 19, 23)

The correct answer is

(15, 26, 31)

Understanding the Number Analogy Problem

This question asks us to identify a set of numbers from the options that shares the same relationship as the numbers in the two given sets: (16, 22, 28) and (14, 19, 23). We are instructed to perform operations on the whole numbers themselves, not their individual digits.

To solve this number analogy problem, we first need to discover the pattern or relationship that connects the three numbers within each of the given sets. Once we understand this relationship, we will apply it to the numbers in the options to find the matching set.

Analyzing the Given Number Sets to Find the Pattern

Let's examine the relationship between the numbers in the first set (16, 22, 28) and the second set (14, 19, 23).

Analyzing Set 1: (16, 22, 28)

Let the numbers be $a=16$, $b=22$, and $c=28$.

Let's find the differences between consecutive numbers:

  • Difference between the second and first number: $b-a = 22 - 16 = 6$
  • Difference between the third and second number: $c-b = 28 - 22 = 6$

In this set, the differences are 6 and 6. This is an arithmetic progression.

Analyzing Set 2: (14, 19, 23)

Let the numbers be $a=14$, $b=19$, and $c=23$.

Let's find the differences between consecutive numbers:

  • Difference between the second and first number: $b-a = 19 - 14 = 5$
  • Difference between the third and second number: $c-b = 23 - 19 = 4$

In this set, the differences are 5 and 4. This is not an arithmetic progression, and the pattern of differences (5, 4) is different from the first set (6, 6).

Since the two given sets have different simple arithmetic difference patterns, the underlying relationship must be something else that applies to both sets. Let's look for a relationship involving the numbers and their differences. Let the set be $(a, b, c)$, the first difference be $d_1 = b-a$, and the second difference be $d_2 = c-b$.

Let's test a potential pattern: Is there a consistent relationship between the first number ($a$) and the second difference ($d_2$)?

  • For Set 1 (16, 22, 28): $a=16$, $d_2=6$. Let's calculate $a - d_2 = 16 - 6 = 10$.
  • For Set 2 (14, 19, 23): $a=14$, $d_2=4$. Let's calculate $a - d_2 = 14 - 4 = 10$.

The pattern appears to be: The first number minus the second difference is equal to 10. Let's formally state the pattern:

Pattern: For a set $(a, b, c)$, the relationship is $a - (c-b) = 10$.

Checking the Options Against the Pattern

Now, we will apply this pattern $a - (c-b) = 10$ to each of the given options to find the set that follows the same rule.

Analyzing Option 1: (12, 18, 25)

Here, $a=12$, $b=18$, $c=25$.

  • First difference $b-a = 18 - 12 = 6$.
  • Second difference $c-b = 25 - 18 = 7$.

Check the pattern: $a - (c-b) = 12 - 7 = 5$.

Since $5 \neq 10$, this set does not follow the pattern.

Analyzing Option 2: (13, 21, 27)

Here, $a=13$, $b=21$, $c=27$.

  • First difference $b-a = 21 - 13 = 8$.
  • Second difference $c-b = 27 - 21 = 6$.

Check the pattern: $a - (c-b) = 13 - 6 = 7$.

Since $7 \neq 10$, this set does not follow the pattern.

Analyzing Option 3: (15, 26, 31)

Here, $a=15$, $b=26$, $c=31$.

  • First difference $b-a = 26 - 15 = 11$.
  • Second difference $c-b = 31 - 26 = 5$.

Check the pattern: $a - (c-b) = 15 - 5 = 10$.

Since $10 = 10$, this set follows the pattern.

Analyzing Option 4: (17, 24, 41)

Here, $a=17$, $b=24$, $c=41$.

  • First difference $b-a = 24 - 17 = 7$.
  • Second difference $c-b = 41 - 24 = 17$.

Check the pattern: $a - (c-b) = 17 - 17 = 0$.

Since $0 \neq 10$, this set does not follow the pattern.

Conclusion

Based on the analysis, only the set (15, 26, 31) follows the same relationship as the given sets (16, 22, 28) and (14, 19, 23), which is $a - (c-b) = 10$.

Set a b c $b-a$ (First Difference) $c-b$ (Second Difference) $a - (c-b)$ Follows Pattern ($a - (c-b) = 10$)?
(16, 22, 28) 16 22 28 6 6 $16 - 6 = 10$ Yes
(14, 19, 23) 14 19 23 5 4 $14 - 4 = 10$ Yes
(12, 18, 25) 12 18 25 6 7 $12 - 7 = 5$ No
(13, 21, 27) 13 21 27 8 6 $13 - 6 = 7$ No
(15, 26, 31) 15 26 31 11 5 $15 - 5 = 10$ Yes
(17, 24, 41) 17 24 41 7 17 $17 - 17 = 0$ No

Revision Table: Key Concepts in Number Analogy

Concept Description How it applies here
Number Analogy Identifying a relationship or pattern between numbers in a set and applying it to find a similar set. We found the pattern $a - (c-b) = 10$ that holds for the given sets and the correct option.
Pattern Recognition Observing and identifying recurring relationships, sequences, or rules in data. Analyzing differences between numbers was key to recognizing the pattern $a - (c-b)$.
Logical Reasoning Using logical steps and deductions to arrive at a conclusion. We used logical deduction to test various potential patterns based on the given sets.
Arithmetic Progression A sequence where the difference between consecutive terms is constant. Set 1 is an arithmetic progression (common difference 6), but Set 2 is not, indicating the pattern is not simply an AP.

Additional Information: Tips for Solving Number Pattern Problems

Solving number pattern and number analogy problems often requires exploring different types of relationships between the numbers. Here are some common approaches to consider:

  • Look for differences: Calculate the difference between consecutive numbers. See if there's a constant difference (arithmetic progression) or a pattern in the differences themselves (e.g., differences form an AP).
  • Look for ratios: Calculate the ratio between consecutive numbers. See if there's a constant ratio (geometric progression).
  • Combine operations: The pattern might involve a combination of addition, subtraction, multiplication, or division. For instance, $b = 2a+k$ or $c = a+b-k$.
  • Relationships involving the position: Sometimes the rule depends on the position of the number in the set (first, second, third).
  • Relationships between the first and third number: Check if the third number is related to the first number directly, perhaps through the middle number. For example, $c = a + k \times b$ or $c = a + (b-a) \times m$.
  • Relationships involving squares, cubes, or prime numbers: While less common in basic problems, complex patterns might involve these.
  • Test simple hypotheses first: Start by checking for basic arithmetic or geometric progressions before moving to more complex relationships like the one found in this problem ($a - (c-b) = constant$).

Practicing with various types of number pattern questions helps in developing the intuition to quickly spot the correct relationship.

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Important Questions from Number Arrangement

  1. Six friends A, B, C, D, E and F are sitting in two lines, facing the north. Three persons are sitting in each line. F is sitting in the middle. C is just behind B. D is to the immediate right of E. B is to the immediate left of F. Which three persons are sitting in the same line?

  2. In the series 5442673314884743581, the number of 4s that are completely divisible by the number on their right but not divisible by the number on their left is:

  3. Refer to the following series and answer the question (all numbers are single digit numbers only).

    (Left) 1 2 6 5 6 8 1 5 8 6 9 8 3 3 5 8 9 4 7 8 (Right)

    How many such even digits are there, each of which is immediately preceded by an odd digit and also immediately followed by an odd digit?

  4. Each of the digits in the number 9362145 is arranged in ascending order from left to right. What will be the sum of the digits which are second from the left and third from the right in the number thus formed?

  5. If 1 is added to each odd digit and 2 is subtracted from each even digit in the number 3842675, how many digits will appear more than once in the new number thus formed?

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