Bank Exam Speed Maths Master Series – Page 14
Mixture & Alligation Tricks & Fast Calculation Methods
Learn Mixture & Alligation shortcut tricks, aptitude formulas, and fast calculation methods for Bank Exams, SSC, Railways, Insurance, and Competitive Exams.
Importance of Mixture & Alligation in Competitive Exams
Mixture & Alligation is one of the most important arithmetic topics in:
- Bank Exams
- SSC
- Railway Exams
- Insurance Exams
- Quantitative Aptitude
This topic is highly useful in:
- Profit & Loss
- Percentage calculations
- Ratio & Proportion
- Business mathematics
- Data Interpretation
🎯 What is Mixture?
Mixture means combining two or more quantities into a single quantity.
Examples:
- Milk & Water
- Gold mixtures
- Chemical mixtures
- Price mixtures
🎯 What is Alligation?
Alligation is a shortcut method used to compare:
- Mean price
- Mean percentage
- Mean concentration
Basic Alligation Formula
Trick 1: Basic Alligation Method
Example:
Rice worth ₹40/kg and ₹60/kg mixed to get mixture worth ₹50/kg
Apply alligation:
60 − 50 = 10
50 − 40 = 10
Ratio:
10 : 10
✅ Answer = 1 : 1
Trick 2: Unequal Difference Method
Example:
Milk worth ₹20/litre and ₹30/litre mixed to get ₹24/litre
Higher difference:
30 − 24 = 6
Lower difference:
24 − 20 = 4
Ratio:
6 : 4
3 : 2
✅ Answer = 3 : 2
Trick 3: Water & Milk Mixture
Example:
Milk : Water = 4 : 1
Total mixture = 25 litres
Total parts = 5
Milk:
25 × 4/5 = 20 litres
Water:
25 × 1/5 = 5 litres
✅ Answer = 20 litres milk, 5 litres water
Trick 4: Replacement Method
Formula:
1Where:
- x = quantity removed
- y = total quantity
- n = number of operations
Example:
A vessel contains 100 litres milk.
20 litres removed and replaced twice.
Remaining milk:
100(1−20/100)²
100(0.8)²
100 × 0.64
✅ Answer = 64 litres
Trick 5: Mean Price Shortcut
Example:
10 kg rice at ₹40/kg
20 kg rice at ₹50/kg
Mean price:
(10×40 + 20×50)/30
1400/30
✅ Answer = ₹46.67/kg
Important Observation Trick
In alligation:
- Cross difference method is fastest
- Ratio comes diagonally
Important Mixture & Alligation Shortcuts
| Topic | Shortcut |
|---|---|
| Alligation | Cross difference |
| Mean Price | Weighted average |
| Water-Milk | Ratio parts method |
| Replacement | Remaining formula |
| Mixture Ratio | Difference method |
Practice Questions
- Rice worth ₹30 and ₹50 mixed to get ₹40. Find ratio
- Milk : Water = 3 : 2, total mixture = 25 litres. Find milk quantity
- 15 kg rice at ₹40 and 25 kg rice at ₹60. Find mean price
- A vessel contains 80 litres milk. 20 litres replaced once. Remaining milk = ?
- Sugar solution 20% and 40% mixed to get 30%. Find ratio
✅ Answers
- 1 : 1
- 15 litres
- ₹52.5/kg
- 60 litres
- 1 : 1
Practice cross difference methods, weighted averages, replacement formulas, and ratio simplification daily to improve arithmetic speed and quantitative aptitude solving ability.
Bank Exam Speed Maths Master Series
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