SSC GD Simple Interest

• Introduction: What is Simple Interest?
• The Three Main Friends: Principal, Rate, and Time
  • Principal (P)
  • Rate (R)
  • Time (T)
• The Simple Interest Formula
• Solving SSC GD Simple Interest Questions: Finding SI
• Advanced SSC GD Simple Interest Questions: Finding P, R, or T

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Introduction: What is Simple Interest?

Imagine you lend your friend ₹100. After one year, your friend gives you back ₹110. Why did they give you ₹10 extra?

That extra ₹10 is called Simple Interest (SI).

• Interest is like a small fee you pay for using someone else’s money.
• In the SSC GD Constable 2026 exam, you must quickly calculate this fee.
• Simple Interest is calculated only on the original amount of money.
• Mastering these concepts helps you solve all ssc gd simple interest questions.

The Three Main Friends: Principal, Rate, and Time

To find Simple Interest, we need three important pieces of information.

Principal (P)

• This is the main money you start with.
• It is the amount you borrow or the amount you deposit in a bank.
• Think of it as the starting line in a race.

Rate (R)

• The Rate tells you how much extra money you pay every year.
• It is always given as a percentage (%).
• If the Rate is 5%, it means you pay ₹5 extra for every ₹100 you borrow each year.
• The Rate is very important when solving simple interest ssc gd questions.

Time (T)

• This is how long the money is borrowed or kept.
• Time is usually measured in years.
• If the time is given in months (like 6 months), you must first change it to years ($\frac{6}{12}$ years).

The Simple Interest Formula

This is the most important tool for solving ssc gd simple interest questions pdf problems.

The formula helps you find the extra money (SI) easily.

$$SI=\frac{P\times R\times T}{100}$$

• $P$ = Principal
• $R$ = Rate (in %)
• $T$ = Time (in years)

Total Amount (A)

When you pay back the money, you pay the original money (Principal) plus the extra money (SI).

$$Amount(A)=Principal(P)+SimpleInterest(SI)$$

Solving SSC GD Simple Interest Questions: Finding SI

We will practice finding the Simple Interest (SI) using the formula. These are common ssc gd simple interest questions.

Example 1: Basic Calculation

A bank gives ₹1000 to a person at a Rate of 5% per year for 3 years. How much Simple Interest will the person pay?

Solution:

1. First, let’s understand what we know:

   • Principal (P) = ₹1000
   • Rate (R) = 5%
   • Time (T) = 3 years

2. Now, write down the formula: $$SI=\frac{P\times R\times T}{100}$$

3. Put the numbers in: $$SI=\frac{1000\times 5\times 3}{100}$$

4. Calculate it (We can cancel the zeros first): $$SI=\frac{10\times 5\times 3}{1}$$ $$SI=150$$

5. So, the answer is: The Simple Interest is ₹150.

Example 2: Finding SI and Total Amount

Ramesh deposits ₹5000 in a scheme that offers 8% Simple Interest for 4 years. Find the SI and the total Amount Ramesh will get back.

Solution:

1. First, let’s understand what we know:

   • P = ₹5000
   • R = 8%
   • T = 4 years

2. Calculate the Simple Interest (SI): $$SI=\frac{5000\times 8\times 4}{100}$$

3. Calculate the value:

   • Cancel the two zeros in 5000 and 100: $50\times 8\times 4$
   • $50\times 8=400$
   • $400\times 4=1600$
   • So, SI = ₹1600.

4. Now, find the Total Amount (A):

   • Remember, Amount is Principal plus Interest: $A=P+SI$
   • $A=5000+1600$
   • $A=6600$

5. So, the answer is: The Simple Interest is ₹1600, and the Total Amount is ₹6600. This is a standard format for simple interest ssc gd questions.

Example 3: Time Conversion (Months to Years)

What is the Simple Interest on ₹2400 at 10% per annum for 6 months? This is a tricky problem often found in ssc gd simple interest questions pdf.

Solution:

1. First, list what we know and fix the Time:

   • P = ₹2400
   • R = 10%
   • Time (T) is 6 months. We must change months to years: $T=\frac{6}{12}=\frac{1}{2}$ year (or 0.5 years).

2. Now, write down the formula: $$SI=\frac{P\times R\times T}{100}$$

3. Put the numbers in: $$SI=\frac{2400\times 10\times (1/2)}{100}$$

4. Calculate it:

   • Cancel the zeros: $24\times 10\times (1/2)$
   • $24\times 10=240$
   • Now, divide 240 by 2 (because of the $\frac{1}{2}$): $240÷2=120$

5. So, the answer is: The Simple Interest is ₹120.

Example 4: Mixed Fraction Rate

Calculate the Simple Interest on ₹4000 for 2 years at a Rate of $6\frac{1}{4}$%. This is a common type of ssc gd simple interest questions involving fractions.

Solution:

1. First, fix the Rate (R):

   • $R=6\frac{1}{4}$. Change this mixed fraction to a simple fraction: $\frac{(6\times 4)+1}{4}=\frac{25}{4}$.
   • P = ₹4000
   • T = 2 years

2. Now, write down the formula: $$SI=\frac{P\times R\times T}{100}$$

3. Put the numbers in:

   • We put the fraction $\frac{25}{4}$ in the numerator, and the 4 goes down with the 100. $$SI=\frac{4000\times (25/4)\times 2}{100}$$ $$SI=\frac{4000\times 25\times 2}{100\times 4}$$

4. Calculate it (Simplify carefully):

   • Cancel the two zeros in 4000 and 100: $\frac{40\times 25\times 2}{4}$
   • Now, divide 40 by 4: $10\times 25\times 2$
   • $10\times 25=250$
   • $250\times 2=500$

5. So, the answer is: The Simple Interest is ₹500.

Advanced SSC GD Simple Interest Questions: Finding P, R, or T

Sometimes, the question gives you the SI and asks you to find the Principal, Rate, or Time. We just need to rearrange our main formula.

Example 5: Finding the Rate (R)

A man earned ₹200 as Simple Interest on a Principal of ₹1000 over 4 years. What was the Rate of Interest? This is a key type of ssc gd simple interest questions pdf problem.

Solution:

1. First, list what we know:

   • SI = ₹200
   • P = ₹1000
   • T = 4 years
   • We need to find R.

2. Use the rearranged formula for R:

   • If $SI=\frac{P\times R\times T}{100}$, then $R=\frac{SI\times 100}{P\times T}$

3. Put the numbers in: $$R=\frac{200\times 100}{1000\times 4}$$

4. Calculate it:

   • $200\times 100=20000$
   • $1000\times 4=4000$
   • $$R=\frac{20000}{4000}$$
   • Cancel the zeros: $R=\frac{20}{4}=5$

5. So, the answer is: The Rate of Interest (R) is 5%.

Example 6: Finding the Principal (P)

What Principal amount must be invested to earn ₹450 Simple Interest in 5 years at a Rate of 9% per annum? We need to solve this simple interest ssc gd questions quickly.

Solution:

1. First, list what we know:

   • SI = ₹450
   • T = 5 years
   • R = 9%
   • We need to find P.

2. Use the rearranged formula for P: $$P=\frac{SI\times 100}{R\times T}$$

3. Put the numbers in: $$P=\frac{450\times 100}{9\times 5}$$

4. Calculate it (Simplify carefully):

   • Multiply the top: $450\times 100=45000$
   • Multiply the bottom: $9\times 5=45$
   • $$P=\frac{45000}{45}$$
   • $45000÷45=1000$

5. So, the answer is: The Principal (P) is ₹1000.

Example 7: Finding the Time (T)

In how many years will ₹600 amount to ₹720 at 4% Simple Interest? This is a tricky ssc gd simple interest questions format because we must find the SI first.

Solution:

1. First, find the Simple Interest (SI):

   • Principal (P) = ₹600
   • Amount (A) = ₹720
   • SI = A – P = $720-600=120$.
   • R = 4%. We need to find T.

2. Use the rearranged formula for T: $$T=\frac{SI\times 100}{P\times R}$$

3. Put the numbers in: $$T=\frac{120\times 100}{600\times 4}$$

4. Calculate it:

   • Multiply the top: $12000$
   • Multiply the bottom: $2400$
   • $$T=\frac{12000}{2400}$$
   • Cancel the zeros: $T=\frac{120}{24}$
   • $120÷24=5$

5. So, the answer is: The Time (T) is 5 years.

Example 8: Doubling the Money

At what rate of Simple Interest will a sum of money double itself in 10 years? This is a very common type of ssc gd simple interest questions pdf shortcut problem.

Solution:

1. First, understand “Doubling”:

   • If the money doubles, it means the Principal (P) becomes the Amount (A).
   • If P = ₹100, then A = ₹200.
   • This means the Simple Interest (SI) must be equal to the Principal (P). $SI=A-P=200-100=100$. So, $SI=P$.
   • We know T = 10 years. Let P = 100 and SI = 100.

2. Use the rearranged formula for R: $$R=\frac{SI\times 100}{P\times T}$$

3. Put the numbers in (using P=100 and SI=100): $$R=\frac{100\times 100}{100\times 10}$$

4. Calculate it:

   • We can cancel the 100 on the top and the 100 on the bottom.
   • $$R=\frac{100}{10}$$
   • $R=10$

5. So, the answer is: The Rate (R) is 10%.