Complex Ratio Chain

Complex Ratio Chain problems involve multiple ratios connecting three or more persons (e.g., A:B = 2:3, B:C = 4:5). These problems require combining ratios into a single chain to find individual ages.

10Worksheets
200+Practice Questions
AdvancedDifficulty
3-4 hoursHours to Master

Introduction to Complex Ratio Chain

Complex Ratio Chain problems involve multiple ratios connecting three or more persons (e.g., A:B = 2:3, B:C = 4:5). These problems require combining ratios into a single chain to find individual ages.

Prerequisites

Ratio and proportion LCM concept Connecting multiple ratios Linear equations
Why This Matters: Complex Ratio Chain problems appear in 1-2 questions in mains level exams. They test advanced ratio manipulation skills.

How to Solve Complex Ratio Chain Problems

1

Step 1: Write all given ratios in the form A:B, B:C, C:D etc.

2

Step 2: Identify a common person appearing in two ratios

3

Step 3: Make the common person's value equal using LCM

4

Step 4: Write the combined ratio A:B:C:D in simplest form

5

Step 5: Let actual ages be combined ratio terms multiplied by k

6

Step 6: Use any additional condition (sum, difference, etc.) to find k

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Step 7: Calculate individual ages

Pro Strategy: Always find the person who appears in two ratios to connect them. Use LCM to make common terms equal before combining.

Example Problem

Example: A:B = 2:3, B:C = 4:5. Sum of ages of A, B, C is 105 years. Find each age. Solution: Step 1: A:B = 2:3, B:C = 4:5 Step 2: Common term is B. In first ratio B=3, in second B=4 Step 3: LCM of 3 and 4 = 12 Step 4: A:B = 2:3 = 8:12, B:C = 4:5 = 12:15 Step 5: Combined A:B:C = 8:12:15 Step 6: Let ages be 8k, 12k, 15k Step 7: Sum = 8k+12k+15k = 35k = 105 → k = 3 Step 8: A = 24, B = 36, C = 45 years Answer: A=24, B=36, C=45 years

Pro Tips & Tricks

  • Find the common person in consecutive ratios
  • Use LCM of the common term's values to make them equal
  • Write ratios in the form A:B, B:C to connect easily
  • The combined ratio shows relative ages of all persons
  • Simplify the final ratio to its lowest terms
  • Use multiplier k to convert ratio to actual ages

Shortcut Methods to Solve Faster

Combined ratio = multiply across after making middle terms equal
For three persons: A:B:C = (A×LCM/B₁):LCM:(C×LCM/B₂)
Use cross-multiplication to verify ratio chains

Common Mistakes to Avoid

Not making the common term equal before combining
Using addition instead of LCM to combine ratios
Forgetting to apply the multiplier to all terms
Misaligning terms when writing combined ratio

Exam Importance

Complex Ratio Chain is an important topic for various competitive exams. Here's how frequently it appears:

SSC CGL
1-2 questions
BANKING PO
1-2 questions
RAILWAYS RRB
2-3 questions
CAT
1-2 questions
INSURANCE
1-2 questions

Ready to Master Complex Ratio Chain?

Start with Worksheet 1 and work your way up to expert level! Each worksheet includes:

20 practice questions
Detailed solutions
Step-by-step explanations
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