Class 8 RS Aggarwal Maths Direct and Inverse Proportions Solutions - Free PDF Download
FAQs on RS Aggarwal Class 8 Mathematics Solutions for Chapter-12 Direct and Inverse Proportions
1. Where can I find complete and accurate solutions for RS Aggarwal Class 8 Maths Chapter 12, Direct and Inverse Proportions?
You can access the complete, step-by-step solutions for all exercises in RS Aggarwal Class 8 Maths Chapter 12 on this page. Our subject experts have solved every question from Exercises 12A, 12B, and 12C, ensuring each solution follows the correct methodology as per the latest CBSE 2025-26 guidelines.
2. What are the key topics covered in the solutions for RS Aggarwal Class 8 Chapter 12?
The solutions for Chapter 12, Direct and Inverse Proportions, provide detailed methods for understanding and solving problems related to:
- Identifying quantities in direct proportion and using the formula x₁/y₁ = x₂/y₂.
- Recognising quantities in inverse proportion and applying the formula x₁y₁ = x₂y₂.
- Solving practical word problems based on speed-distance-time, time-work, and cost-quantity scenarios.
- Distinguishing between the two types of variations to select the correct problem-solving approach.
3. How do I identify whether a word problem involves direct or inverse proportion?
To correctly identify the relationship, analyse how the two quantities behave together.
- It is a direct proportion if an increase in one quantity causes a proportional increase in the other (e.g., more items purchased leads to a higher total cost).
- It is an inverse proportion if an increase in one quantity causes a proportional decrease in the other (e.g., increasing the speed of a vehicle reduces the time taken to cover a fixed distance).
4. What is the fundamental difference between the formulas used for direct proportion (x/y = k) and inverse proportion (xy = k)?
The fundamental difference lies in the constant value 'k' that defines the relationship:
- For direct proportion, the ratio of the two variables (x and y) is constant. The formula is x/y = k, or more commonly for problem-solving, x₁/y₁ = x₂/y₂.
- For inverse proportion, the product of the two variables is constant. The formula is x × y = k, which leads to the problem-solving equation x₁y₁ = x₂y₂.
5. Why is it important to use the correct step-by-step method shown in the RS Aggarwal solutions for exams?
Using the correct step-by-step method is critical for scoring full marks in exams. As per the CBSE evaluation process, marks are often awarded for each logical step, not just the final answer. A complete solution demonstrates your understanding and should include:
- Identifying the given quantities.
- Stating whether the proportion is direct or inverse.
- Writing the correct formula.
- Showing accurate calculations.
- Concluding with the final answer and appropriate units.
6. Which exercises in RS Aggarwal Class 8 Chapter 12 are considered most important for exams?
While all exercises are important for building a strong foundation, students often find the application-based word problems in Exercise 12B and 12C to be particularly crucial. These questions test the ability to apply the concepts of inverse proportion to real-world scenarios like 'time and work' or 'provisions for a garrison', which are common in examinations.
7. What are some common mistakes to avoid when solving problems on direct and inverse proportions?
A common mistake is incorrectly identifying the type of proportion. Students sometimes apply the direct proportion formula to an inverse proportion problem, or vice-versa. Another frequent error is mixing up the values (e.g., swapping x₂ and y₂). To avoid this, always write down the variables clearly (e.g., let 'x' be the number of workers and 'y' be the time taken) and double-check the relationship before calculating.
















