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Question

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

(NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into their constituent digits. E.g. 13 - Operations on 13 such as adding / substracting / 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.)

(7, 15, 11)

(9, 19, 14)

The correct answer is

(11, 23, 17)

Understanding Number Set Relationships

This question asks us to find a set of numbers among the options that shares the same mathematical or logical relationship as the two example sets provided: (7, 15, 11) and (9, 19, 14).

It's important to note the constraint given: operations should be performed on the whole numbers as they are, without breaking them down into their individual digits. For example, we can use 13 as a whole number for operations like addition or multiplication, but we cannot separate 1 and 3 to perform calculations.

Analyzing the Given Number Sets to Find the Pattern

Let's examine the relationship between the numbers in the two provided sets. We'll try to find a consistent rule that connects the first, second, and third numbers in each set.

Set 1: (7, 15, 11)

  • Let the numbers be represented as A, B, and C, where A = 7, B = 15, and C = 11.
  • We look for a rule connecting A, B, and C.

Let's explore some common relationships:

  • Relationship between A and B: We can see that $15 = 7 \times 2 + 1$. This suggests a rule like $B = 2A + 1$.
  • Relationship between A and C: $11 = 7 + 4$. This suggests $C = A + 4$.
  • Relationship between B and C: $11 = 15 - 4$. This suggests $C = B - 4$.
  • Relationship involving all three: What about the average of A and B? $(7 + 15) / 2 = 22 / 2 = 11$. This matches C. This suggests a rule $C = (A + B) / 2$.

Set 2: (9, 19, 14)

  • Let A = 9, B = 19, and C = 14.
  • Now, let's test the potential patterns found from Set 1 on this second set to see which one is consistent.
  • Test $B = 2A + 1$: $2 \times 9 + 1 = 18 + 1 = 19$. This matches B (19). The rule $B = 2A + 1$ works for both sets.
  • Test $C = A + 4$: $9 + 4 = 13$. This does not match C (14).
  • Test $C = B - 4$: $19 - 4 = 15$. This does not match C (14).
  • Test $C = (A + B) / 2$: $(9 + 19) / 2 = 28 / 2 = 14$. This matches C (14). The rule $C = (A + B) / 2$ works for both sets.

From the analysis of both sets, we find a consistent pair of relationships governing the numbers A, B, and C:

  1. The second number (B) is calculated as twice the first number (A) plus one: $B = 2A + 1$.
  2. The third number (C) is the average of the first and second numbers: $C = \frac{A + B}{2}$.

Checking Options Against the Pattern

Now we will examine each of the given options to see which set follows the identified pattern ($B = 2A + 1$ and $C = (A + B) / 2$).

Option Set (A, B, C) Check Rule 1: $B = 2A + 1$ Check Rule 2: $C = (A + B) / 2$ Follows the Pattern?
(11, 23, 17) $2 \times 11 + 1 = 22 + 1 = 23$ (Matches B=23) $(11 + 23) / 2 = 34 / 2 = 17$ (Matches C=17) Yes
(13, 25, 21) $2 \times 13 + 1 = 26 + 1 = 27$ (Does not match B=25) - No
(6, 13, 9) $2 \times 6 + 1 = 12 + 1 = 13$ (Matches B=13) $(6 + 13) / 2 = 19 / 2 = 9.5$ (Does not match C=9) No
(8, 16, 13) $2 \times 8 + 1 = 16 + 1 = 17$ (Does not match B=16) - No

Conclusion

Only the option set (11, 23, 17) satisfies both relationships discovered from the example sets: the second number is $2A + 1$ and the third number is the average of the first two numbers, $(A + B) / 2$.

Therefore, the set (11, 23, 17) is related in the same way as the numbers of the given sets (7, 15, 11) and (9, 19, 14).

Revision Table: Reasoning Number Patterns

Concept Explanation Application
Number Set Analogy Identifying how numbers in a group are mathematically or logically connected. Finding the hidden rule in given sets.
Pattern Identification Observing examples to deduce the consistent rule or relationship. Key skill for solving reasoning puzzles and analogies.
Rule Application Testing the discovered rule against new sets of numbers (options). Confirming which set follows the same pattern.

Additional Information: Strategies for Number Relationship Questions

Questions involving number set relationships require you to be systematic in exploring possibilities. Here are some strategies:

  • Start with simple arithmetic: Look for sums, differences, products, or quotients between pairs of numbers in the set.
  • Consider operations involving all three numbers: Check for relationships like the third number being the sum, difference, product, quotient, or average of the first two.
  • Look for sequences or series: Sometimes the numbers follow a progression based on a simple rule (e.g., add a constant, multiply by a constant, or a combination).
  • Check for powers or roots: See if squaring, cubing, or taking square/cube roots are involved.
  • Always test your hypothesis on ALL provided examples. A rule must work for every given set.
  • If one rule doesn't work, try combining operations or looking for two simultaneous rules, as seen in this problem ($B = 2A + 1$ and $C = (A + B) / 2$).
  • Systematically check each option against the confirmed rule(s).
  • Pay close attention to any specific conditions mentioned in the question, such as the one about not breaking down digits.

Practice is key to quickly spotting patterns in number set analogy problems.

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Important Questions from Letter and Number Based

  1. Select the option in which the numbers are related in the same way as are the numbers of the following set.

    (4, 8, 16)

  2. Select the option that is related to the third number in the same way as the second number is related to the first number.

    23 : 441 : : 28 : ?

  3. Select the option that is related to the third number in the same way as the second number is related to the first number and the sixth number is related to the fifth number.

    12 : 72 ∷ 18 : ? ∷22 : 242
  4. Select the option that is related to the third number in the same way as the second number is related to the first number.

    7 : 56 :: 11 : ?

  5. Select the option in which the numbers are related in the same way as are the numbers of the following set.

    (12, 60, 84)

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