RS Aggarwal Solutions Class 8 Chapter-11 Compound Interest (Ex 11C) Exercise 11.3 - Free PDF

Q: 5. What is the most common mistake students make when solving questions from RS Aggarwal Ex 11C?

A very common mistake is confusing the final Amount (A) with the Compound Interest (CI). Many students correctly calculate the total amount using the formula but forget to perform the final step of subtracting the original principal (CI = A - P) to find the interest. It is crucial to read the question carefully to determine whether it asks for the final amount or just the interest earned.

RS Aggarwal for Class 8 Mathematics Solutions Chapter-11

RS Aggarwal for Class 8 Mathematics is one of the best and renowned reference books for students and teachers. It covers questions of varied difficulty level, from basic to advanced questions, where students can learn all the important questions. All these solutions are provided by the expert teachers of Vedantu in a comprehensive way. To help students build their core knowledge on the subject, Vedantu provides RS aggarwal Solutions for Class 8, Chapter 11- Compound Interest for free in PDF format.

Chapter 11- Compound Interest

This chapter is based on the topics of compound interest and simple interest. In this chapter, you will learn about terms like rate of interest, time period, per annum, and half-yearly, the value of an item after compound interest, compound interest for different time periods like annually, two years, three years, and so on.

This chapter is divided into 4 exercises (Exercise- 11A, 11B, 11C, 11D) and consists of 63 questions overall.

Exercise 11A consists of 8, where you just have to calculate the simple interest and the compound interest using the formula.
Exercise 11B consists of 30 questions and deals with compound interest of more than one rate of interest. In some questions, the final amount after applying the interest will be given and you have to calculate the original value.
Exercise 11C consists of 10 word-related problems.
Exercise 11D has 15 word-related problems, where all the questions are based on finding the compound interest.

To learn these concepts in an easy manner with in-depth understanding, Vedantu provides RS Aggarwal Solution for Class 8 Chapter 11- Playing with Numbers, (Ex- 11C) Exercise 11.3- PDF for free.

FAQs on RS Aggarwal Solutions Class 8 Chapter-11 Compound Interest (Ex 11C) Exercise 11.3 - Free PDF

1. What is the fundamental formula used for solving problems in RS Aggarwal Class 8, Chapter 11 on Compound Interest?

The fundamental formula used to calculate the final amount (A) in this chapter is A = P(1 + R/100)ⁿ, where 'P' represents the principal amount, 'R' is the annual rate of interest, and 'n' is the time period in years. To find only the Compound Interest (CI), you must subtract the principal from the final amount: CI = A - P. These solutions focus on applying this formula correctly to different scenarios.

2. What is the correct step-by-step method to solve a word problem from RS Aggarwal Class 8 Maths Ex 11C?

To accurately solve a word problem from Exercise 11C, you should follow this method:

Step 1: Read the problem carefully to identify the given values: Principal (P), Rate (R), and Time (n).
Step 2: Check the compounding frequency (e.g., annually or half-yearly) and adjust R and n if needed.
Step 3: Substitute these values into the correct formula: A = P(1 + R/100)ⁿ.
Step 4: Calculate the total Amount (A).
Step 5: If the question asks for the Compound Interest (CI), perform the final calculation: CI = A - P.

3. What types of questions are covered in Exercise 11C of RS Aggarwal's Chapter 11?

Exercise 11C of RS Aggarwal's Chapter 11 primarily contains word problems based on real-life applications of compound interest. These questions test a student's ability to extract the correct values for principal, rate, and time from a descriptive scenario and apply the compound interest formula to find either the total amount or the interest accrued, typically on an annual compounding basis.

4. How does the calculation method change for problems with half-yearly compounding in this chapter?

When interest is compounded half-yearly, the calculation method is adjusted to reflect two compounding periods within one year. You must:

Halve the annual rate of interest (R/2), as the rate is applied per six-month period.
Double the time period (2n), as the number of compounding periods increases.

The formula then becomes A = P(1 + (R/2)/100)²ⁿ. Getting this adjustment right is a key step for solving such problems correctly.

5. What is the most common mistake students make when solving questions from RS Aggarwal Ex 11C?

A very common mistake is confusing the final Amount (A) with the Compound Interest (CI). Many students correctly calculate the total amount using the formula but forget to perform the final step of subtracting the original principal (CI = A - P) to find the interest. It is crucial to read the question carefully to determine whether it asks for the final amount or just the interest earned.

6. Why is it important to show a step-by-step calculation for compound interest problems in exams?

Using a clear, step-by-step method is crucial in exams for several reasons. It demonstrates your understanding of the process, from identifying variables to applying the formula. This structured approach helps in minimising calculation errors. Furthermore, as per the CBSE evaluation guidelines, showing your work can help you secure partial marks for the correct formula and substitution, even if the final answer has an error.

7. How is the calculation of Compound Interest different from that of Simple Interest in Class 8 Maths?

The main difference lies in how the principal is treated. For Simple Interest, the principal amount remains constant for every time period. For Compound Interest, the interest from the first period is added to the principal to form a new, larger principal for the second period. This concept of earning 'interest on interest' makes the final amount grow much faster compared to simple interest over the same period.