Ratio Chain

Ratio Chain problems involve multiple age relationships expressed as ratios between different pairs of persons. These problems require connecting ratios into a single chain to find individual ages or a common multiplier.

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

Introduction to Ratio Chain

Ratio Chain problems involve multiple age relationships expressed as ratios between different pairs of persons. These problems require connecting ratios into a single chain to find individual ages or a common multiplier.

Prerequisites

Ratio and proportion LCM concept Connecting multiple ratios
Why This Matters: Ratio Chain problems test your ability to work with multiple ratios simultaneously. They appear in 1-2 questions in mains level exams.

How to Solve Ratio Chain Problems

1

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

2

Step 2: Connect ratios by finding a common term between consecutive ratios

3

Step 3: Make the common term equal by using LCM of its values

4

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

5

Step 5: Use a common multiplier k to express actual ages

6

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

Pro Strategy: Connect ratios through common terms. Always simplify the combined ratio to its lowest terms before applying the multiplier.

Example Problem

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

Pro Tips & Tricks

  • Find the person who appears in two ratios to connect them
  • Use LCM to make common terms equal
  • Write ratios in the form A:B, B:C to connect easily
  • The combined ratio shows relative ages of all persons
  • Multiply each ratio term by the same factor to maintain proportion
  • Check if the combined ratio can be simplified further

Shortcut Methods to Solve Faster

Combined ratio = multiply across after making middle terms equal
For three persons: A:B and B:C → 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

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

Ready to Master 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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