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RS Aggarwal Solutions

RS Aggarwal Solutions Class 7 Chapter-12 Simple Interest (Ex 12A) Exercise 12.1

RS Aggarwal Solutions Class 7 Chapter-12 Simple Interest (Ex 12A) Exercise 12.1

Q: 3. How do I correctly handle time when it is given in months or days in an Ex 12A problem?

The standard formula for Simple Interest requires the Time (T) to be expressed in years. If the question provides time in other units, you must convert it:For months: Divide the number of months by 12. For example, 8 months would be calculated as 8/12 years.For days: Divide the number of days by 365 (unless a leap year is specified). For example, 146 days would be 146/365 years.

Q: 4. What is the key difference between questions asking for 'Simple Interest' and those asking for 'Amount'?

This is a common point of confusion. The Simple Interest (SI) is only the additional money earned or paid as interest. The Amount (A) is the total sum after the interest has been added. So, calculating the 'Amount' is a two-step process: first, you find the SI, and then you must add this SI back to the original Principal (P).

Q: 6. Why is this chapter named 'Simple' Interest, and what makes it simple?

It is called Simple Interest because the interest is calculated only on the original Principal (P) for the entire duration of the loan or investment. The interest earned each year does not change. This is unlike compound interest (a more advanced topic), where interest is also earned on the accumulated interest from previous years, making the calculation more complex.

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RS Aggarwal Solutions Class 7 Chapter-12 Simple Interest (Ex 12A) Exercise 12.1 - Free PDF

To build a good foundation in mathematics, it is essential to learn it from the experts from the beginning. The subject matter experts have provided RS Aggarwal Solutions Class 7 Math Chapter 12a in an easily understandable manner. The RS Aggarwal Class 7 Math Exercise 12a Solutions are based on the latest CBSE curriculum, and every topic is explained in simple steps. These RS Aggarwal Solutions Class 7 Math Exercise 12a would help students understand the concepts of Simple Interest through various kinds of sums and their solutions.

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RS Aggarwal Class 7 Math Exercise 12 A

The questions in Class 7 Math RS Aggarwal Exercise 12a cover all the important aspects of the Simple Interest topic where one has to find Simple interest, amount, rate, or time, based on the given parameters. Students will learn about the following important concepts in RS Aggarwal Solutions Class 7 Math Chapter 12a:

Simple Interest - Simple Interest or S.I. is the method applied to find out the interest when a principal amount is lent at a specific rate of interest and specified time duration.
Formula to Calculate Simple Interest - Simple interest is given by the following formula:

S.I = (P * R * T)/100.

Where P - the principal amount

R - the rate of interest in percentage

T - the time period in years.

Formula to Calculate the Total Amount - The total amount which is payable after a duration of T years is found by the formula:

Amount (A) = Principal (P) + Simple Interest (S.I)

The Formula For S.I in Months - If one is given the time duration in months then the formula to calculate the Simple Interest would be:

S.I = (P * n * R)(12 * 100), where n is the number of months.

Let Us Understand These Concepts With A Few Problems:

Mr.X takes a loan from a bank for Rs 20,000, which lends the money at a 10% rate of interest. What is the total amount payable by Mr.X to the bank after 5 years:

To get the total amount due, let us first calculate the Simple Interest which is, S.I = (P * R * T)/100 = (20,000 * 10 * 5)/100 = 10,000

Total Amount payable after 5 years = P + S.I = 20,000 + 10,000 = 30,000

Ms. Y pays a total amount of 9000 to Mr Z for an amount of 7000 lent by Mr Z to Ms Y for 2 years. Calculate the rate of interest that Mr Z charges Ms Y on the amount lent.

Amount = S.I + P

S.I = Amount - P = 9000 - 7000 = 2000

(7000 * r * 2)/100 = 2000

Hence rate of interest, r = (2000 * 100)/(7000 * 2) = 14.29%

Preparation Tips for RS Aggarwal Class 7 Math Exercise 12 A

Try to do as many questions as possible on Simple Interest. As you keep doing questions of different kinds, you will be able to memorize the formulas better.
For calculating S.I where time is split into years and months like 3 years 2 months, remember that there are 12 months in a year. So, you need to convert the years into months and then divide the R.H.S of Simple Interest formula by 12. So here you will get 3 years = 3 * 12 = 36 months. Total months = 36 + 2 = 38 months, now you will put it in the S.I formula as:

S.I = (P * r * 38)/(12 * 100)

Conclusion

Simple interest taught in RS Aggarwal Solutions Math Class 7 Chapter 12 forms the basis for the more complex calculation of compound interest. Therefore students must get ample practice in this topic. Going through RS Aggarwal Solutions Class 7 Math Chapter 12a students can surely secure good grades in exams and be better prepared to solve any question on this topic.

FAQs on RS Aggarwal Solutions Class 7 Chapter-12 Simple Interest (Ex 12A) Exercise 12.1

1. How should I start solving a problem from RS Aggarwal Class 7 Maths, Exercise 12A?

The first step is always to carefully read the question and identify the given information. You need to list down the three key components for any simple interest calculation: the Principal (P), which is the initial amount of money; the Rate of Interest (R), usually given per annum; and the Time (T), which must be in years. Writing these down first helps you substitute them correctly into the formula.

2. What are the main formulas I need to know for solving questions in RS Aggarwal Chapter 12, Ex 12A?

For this exercise, you need to master two fundamental formulas:

To find the Simple Interest (SI): SI = (P × R × T) / 100
To find the total Amount (A) at the end of the period: Amount (A) = Principal (P) + Simple Interest (SI)

Understanding how and when to use these is essential for all problems in this exercise.

3. How do I correctly handle time when it is given in months or days in an Ex 12A problem?

The standard formula for Simple Interest requires the Time (T) to be expressed in years. If the question provides time in other units, you must convert it:

For months: Divide the number of months by 12. For example, 8 months would be calculated as 8/12 years.
For days: Divide the number of days by 365 (unless a leap year is specified). For example, 146 days would be 146/365 years.

4. What is the key difference between questions asking for 'Simple Interest' and those asking for 'Amount'?

This is a common point of confusion. The Simple Interest (SI) is only the additional money earned or paid as interest. The Amount (A) is the total sum after the interest has been added. So, calculating the 'Amount' is a two-step process: first, you find the SI, and then you must add this SI back to the original Principal (P).

5. Why is the interest rate (R) divided by 100 in the simple interest formula?

The division by 100 is because the rate of interest is given as a 'per cent' (%), which literally means 'per hundred'. For example, a rate of 5% means 5 for every 100. The formula SI = (P × R × T) / 100 mathematically applies this concept by converting the percentage rate into a fraction (R/100) to calculate the actual interest value on the principal.

6. Why is this chapter named 'Simple' Interest, and what makes it simple?

It is called Simple Interest because the interest is calculated only on the original Principal (P) for the entire duration of the loan or investment. The interest earned each year does not change. This is unlike compound interest (a more advanced topic), where interest is also earned on the accumulated interest from previous years, making the calculation more complex.

7. If I am stuck on a question in Ex 12A, what is the best way to use the RS Aggarwal solutions?

The most effective way is to first try solving the problem on your own. If you are unable to proceed, refer to the step-by-step solution to understand the logic and method. Pay close attention to how the Principal, Rate, and Time were identified and how the formula was applied. The goal is not just to get the answer but to learn the correct problem-solving process.

8. How do I solve a problem in Ex 12A that asks to find the Principal (P) when the Simple Interest, Rate, and Time are given?

You can solve this by rearranging the basic Simple Interest formula. The original formula is SI = (P × R × T) / 100. To find the Principal, you can modify this formula to isolate 'P':

P = (SI × 100) / (R × T)

By using this rearranged formula, you can directly substitute the given values of SI, R, and T to find the original principal amount.