Ratio and Proportion Made Simple

Introduction

Ratio and Proportion are fundamental topics in aptitude exams and are often linked with Percentages, Averages, and Mixtures. Once you understand the logic behind them, many seemingly tough questions become straightforward.

In this article, we will explore the basics, formulas, and shortcuts used in placement tests.

---

What is a Ratio?

A ratio compares two quantities of the same kind.

Formula:
Ratio = Quantity A : Quantity B

Example:
If there are 10 boys and 5 girls in a class,
Ratio of Boys to Girls = 10 : 5 = 2 : 1

---

What is Proportion?

Proportion states that two ratios are equal.

Formula:
a : b = c : d
or
a/b = c/d

Example:
2 : 3 = 4 : 6 → Both represent the same ratio.

---

Key Properties

• Cross Multiplication:
  If a : b = c : d → a × d = b × c

• Scaling:
  Multiplying or dividing both terms by the same number does not change the ratio.

---

Shortcut Trick (Exam Favorite)

If quantities increase or decrease in the same ratio, the overall proportion remains unchanged.
Instead of recalculating everything, simplify ratios first.

---

Common Mistakes to Avoid

• Comparing different units without conversion
• Forgetting to simplify ratios
• Ignoring order of terms

---

Why Ratio & Proportion Matter in Placements

• Frequently asked directly
• Used in Mixtures & Allegations, Time & Work, and Speed Problems
• Improves logical thinking speed

Mastering this topic makes multi-step aptitude problems easier.

---

Conclusion

Ratio and Proportion are not about heavy calculations but about recognizing relationships. Practice simplification and cross multiplication regularly for speed.

👉 Take the test below to check your understanding.