Co-relation - Numbers
Introduction
Co-relation or Analogy in numbers involves identifying a specific relationship between the first two numbers and applying the same logic to find the missing fourth number.
Explanation Step by Step
To solve Co-relation questions, follow these steps:
- Analyze the mathematical operation (Addition, Subtraction, Multiplication, Division) between the first pair.
- Check for digit-based relations like the sum of digits.
- Verify if the same logic applies to the options provided for the second pair.
Sub-topics
Numbers
Finding the numerical pattern such as half-values, squares, or digit sums.
Examples
Example 1
Pair: 24 : 10 :: 36 : ?
Logic: (24 / 2) - 2 = 10.
Logic: (24 / 2) - 2 = 10.
Answer: (36 / 2) - 2 = 16.
Example 2
Pair: 243 : 144 :: 952 : ?
Logic: Sum of digits of 243 (2+4+3) = 9. Sum of digits of 144 (1+4+4) = 9.
Logic: Sum of digits of 243 (2+4+3) = 9. Sum of digits of 144 (1+4+4) = 9.
Answer: Sum of 952 (9+5+2) = 16. Look for an option where digits sum to 16, like 754.
Tricks and Shortcuts
Always check for the "Sum of Digits" first if the numbers are large. For smaller numbers, check for multiplication or division relations.
Common Mistakes
Applying a logic that works for the first pair but is not consistent with the options provided for the second pair.
Practice Questions
Easy Questions
- 10 : 20 :: 30 : ? (Options: 1) 40, 2) 50, 3) 60, 4) 70)
- 5 : 25 :: 6 : ? (Options: 1) 30, 2) 36, 3) 40, 4) 42)
- 100 : 50 :: 200 : ? (Options: 1) 150, 2) 100, 3) 50, 4) 120)
Medium Questions
- 44 : 22 :: 88 : ? (Options: 1) 44, 2) 33, 3) 22, 4) 11)
- 23 : 5 :: 41 : ? (Options: 1) 4, 2) 5, 3) 6, 4) 7)
- 12 : 24 :: 18 : ? (Options: 1) 30, 2) 36, 3) 40, 4) 42)
Hard Questions
- 50 : 23 :: 70 : ? (Options: 1) 33, 2) 35, 3) 40, 4) 45)
- 111 : 3 :: 222 : ? (Options: 1) 4, 2) 5, 3) 6, 4) 9)
- 9 : 81 :: 11 : ? (Options: 1) 110, 2) 121, 3) 131, 4) 100)
Revision Summary
Mastering number co-relation requires a strong grasp of basic arithmetic and pattern recognition.