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Question

Four number-pairs have given, out of which three are alike in some manner and one is different. Select the number-pair that is different from the rest.

This question was previously asked in
SSC CGL 2019 (Tier 2) GS Finance & Economics Previous Year Paper (17-Nov-2020)
The correct answer is

15 : 250

Finding the Different Number Pair

The question asks us to identify the number pair that is different from the rest among four given pairs. We need to look for a pattern or rule that applies to three of the pairs but not the fourth one.

Analyzing the Given Number Pairs

Let's examine each number pair to find a relationship between the two numbers in the pair.

  • Pair 1: 17 : 289
  • Pair 2: 11 : 121
  • Pair 3: 15 : 250
  • Pair 4: 13 : 169

Checking for a Consistent Pattern

A common pattern in such questions involves mathematical operations like addition, subtraction, multiplication, division, or squaring/cubing the first number to get the second number.

Let's check if the second number is the square of the first number in each pair:

Number Pair First Number Second Number First Number Squared ($n^2$) Does it match?
17 : 289 17 289 $\text{17}^2 = \text{17} \times \text{17} = 289$ Yes
11 : 121 11 121 $\text{11}^2 = \text{11} \times \text{11} = 121$ Yes
15 : 250 15 250 $\text{15}^2 = \text{15} \times \text{15} = 225$ No
13 : 169 13 169 $\text{13}^2 = \text{13} \times \text{13} = 169$ Yes

Identifying the Different Pair

From the analysis above, we can see the following:

  • In the pair 17 : 289, the second number (289) is the square of the first number (17).
  • In the pair 11 : 121, the second number (121) is the square of the first number (11).
  • In the pair 13 : 169, the second number (169) is the square of the first number (13).
  • In the pair 15 : 250, the second number (250) is not the square of the first number (15), as $\text{15}^2 = 225$.

Therefore, the number pair 15 : 250 does not follow the same pattern as the other three pairs.

Conclusion

The number-pair that is different from the rest is 15 : 250.

Revision Table: Number Pair Analysis

Reviewing the pattern observed:

Pair Pattern Result
17 : 289 Second number is square of first $17^2 = 289$ (Matches)
11 : 121 Second number is square of first $11^2 = 121$ (Matches)
15 : 250 Second number is square of first $15^2 = 225$ (Does not match 250)
13 : 169 Second number is square of first $13^2 = 169$ (Matches)

Additional Information: Finding Patterns in Number Series and Pairs

Problems involving finding the different number pair often rely on identifying mathematical relationships. These can include:

  • Squares and Cubes: Checking if one number is the square or cube of the other.
  • Arithmetic Operations: Looking for patterns involving addition, subtraction, multiplication, or division between the numbers, or between the numbers and their positions.
  • Prime/Composite Numbers: One number in the pair might be prime, while the other is composite, or the numbers themselves might follow a prime/composite pattern.
  • Digit Sums: The sum of the digits of one number might relate to the other number.
  • Specific Series: The numbers might be part of a known sequence like Fibonacci, etc.

To solve such problems, it's helpful to test common patterns systematically until one fits most of the options.

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Similar Questions

  1. Identify the roll number that doesn't fit this rule.
    Last 3 digits = First 3 digits + 100
  2. If 2 * 3 = 8, 3 * 4 = 81, then 4 * 5 = ?
  3. Find the missing number: 17 : 4914 :: 19 : ?
  4. Find the missing number: $23 : 125 :: 31 : ?$

  5. How many of these roll numbers are palindromes? List: 123321, 654456, 112211, 123456

  6. The second number in the given number-pairs is obtained by performing certain mathematical operation(s) on the first number. The same operation(s) is/are followed in all the number-pairs except one. Find that odd number-pair.

  7. Three of the following four triads are alike in a certain way as they are formed by performing same mathematical operations among themselves and thus form a group. Which triad does NOT belong to that group?

  8. The second number in the given number-pairs is obtained by performing certain mathematical operation(s) on the first number. The same operation(s) is/are followed in all the number-pairs, except one. Find that odd number-pair.

    (NOTE: The relation should be found without breaking down the numbers into its constituent digits)

  9. The second number in the given number pairs is obtained by performing certain mathematical operation(s) on the first number. The same operation(s) are followed in all the number pairs, EXCEPT one. Find that odd number pair.

  10. Three of the following four triads are alike in a certain way as they are formed by performing same mathematical operations among themselves and thus form a group. Which triad does NOT belong to that group?


Important Questions from Number Based

  1. Four number triads have been given, out of which three are alike in some manner and one is different. Select the number triad that is different.

  2. Choose the odd number out of the given options.

  3. Identify the odd one from the following.

  4. Identify the number that is different from the rest.

  5. Four numbers have been given out of which three are alike in some manner, while one is different. Choose the odd one.

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