Module ·
Chapter 4: Average, Mixture & Alligation
Arithmetic
4 topics
What this chapter covers
The 4 topics below make up Average, Mixture & Alligation in the SSC CGL exam. Click any topic to open its notes, examples and practice test.
Study material & tests
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Notes, worked examples and hint-guided practice for every topic.
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🎯 Topic tests
8 auto-graded questions per topic, pulled from the question bank.
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📝 Chapter test
25 fresh mixed-difficulty questions, timed, with full solutions.
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Formula Reference Sheet
This chapter
Average
| Average | sum of values / number of values |
|---|---|
| New average on adding x | recompute (old sum + x) / (n + 1) |
| Average speed (equal distances) | 2ab / (a + b) |
Alligation
| Alligation rule | cheaper:dearer = (dearer - mean) : (mean - cheaper) |
|---|---|
| Repeated replacement | final = initial x (1 - r/V)^n |
SSC reference
🖩 Graphing Calculator