RRB NTPC Maths Simple Interest: Formula, Practice, Solved Problems

RRB NTPC Maths Simple Interest: Preparing for the RRB NTPC Maths section can be overwhelming, but mastering key topics like Simple Interest can make all the difference. 

Whether you're just starting or looking to strengthen your understanding, here we will guide you through Simple Interest questions, the Simple Interest formula, and some solved problems to boost your preparation.

RRB NTPC Maths Simple Interest

Simple Interest (SI) is the interest calculated on the original principal amount for a specific time period, usually in years. This concept is crucial for exams like RRB NTPC, as it’s frequently tested.

The formula to calculate Simple Interest is:

SI = (P × R × T) / 100

Where:

• P = Principal (the original amount)

• R = Rate of Interest (annual)

• T = Time period (in years)

The total Amount (A) after interest is calculated as:

A = P + SI

Understanding and applying this formula correctly will help you solve Simple Interest problems in no time.

Simple Interest Questions for RRB NTPC Maths

Let’s look at a few Simple Interest practice questions to understand how to apply the formula.

1. Basic Simple Interest Problem

Question:
Rahi deposits ₹600 in a bank offering 8% annual simple interest. If Rahi keeps the money in the bank for 5 years, what will be the interest earned?

Solution:
Using the formula for Simple Interest:

SI = (600 × 8 × 5) / 100 = ₹240

So, the interest earned after 5 years will be ₹240, and the right answer is option A.

2. Using Percentage Concept in Simple Interest

Question:
If a sum of ₹800 becomes ₹956 in 3 years, what is the Simple Interest and the Rate of Interest?

Solution:
First, calculate the Simple Interest (SI):

SI = 956 - 800 = ₹156

Now, using the formula for SI:

SI = (P × R × T) / 100

Substitute the known values:

156 = (800 × R × 3) / 100

Solve for R:

R = (156 × 100) / (800 × 3) = 6.5%

So, the rate of interest is 6.5%.

3. Interest Calculation for Different Time Periods

Question:
How much interest will ₹2400 earn in 4.5 years at an annual rate of 4.5%?

Solution:
Convert 4.5 years to 9/2 years, and use the Simple Interest formula:

SI = (2400 × 4.5 × 9/2) / 100 = ₹486

So, the interest earned will be ₹486.

Solved Problems to Boost Your RRB NTPC Maths Practice

Here are some additional Simple Interest solved problems to help you get a better grasp of the concept:

4. Principal and Rate Calculation

Question:
If the interest on a certain amount at 12% per annum for 5 years is ₹6900, find the principal.

Solution:
Using the formula for SI:

SI = (P × R × T) / 100

Substitute the known values:

6900 = (P × 12 × 5) / 100

Solve for P:

P = (6900 × 100) / (12 × 5) = ₹11500

So, the principal amount is ₹11500.

Why Simple Interest Is Important for RRB NTPC?

Understanding Simple Interest is essential for RRB NTPC Maths preparation. The concept is tested in various formats, whether it’s directly asking for a Simple Interest calculation or indirectly using percentage concepts. 

By practicing Simple Interest questions and understanding the formula, you’ll improve your speed and accuracy, which is vital in competitive exams like RRB NTPC.

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