🔹 Meaning of Simple Interest

Simple Interest (SI) is the interest calculated only on the original principal amount, for the entire duration of the loan or investment.
It does not include interest on previously earned interest (unlike compound interest).

Simple interest is commonly used in:

• Short-term loans
• Personal borrowing
• Fixed deposits (in some cases)
• Educational examples
• Basic financial planning

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🔹 Formula of Simple Interest

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

Where:

• SI = Simple Interest
• P = Principal amount (Initial investment or loan)
• R = Rate of interest (per annum in %)
• T = Time (in years)

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🔹 Total Amount Formula

To find the total amount payable or receivable:$$A = P + SI$$A=P+SI

Where:

• A = Final Amount
• P = Principal
• SI = Simple Interest

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🔎 Example 1: Basic Calculation

Problem:

A person invests ₹50,000 at an interest rate of 8% per year for 3 years.
Find the simple interest and total amount.

Step 1: Apply Formula

$$SI = \frac{P \times R \times T}{100}$$SI=100P×R×T​ $$SI = \frac{50,000 \times 8 \times 3}{100}$$SI=10050,000×8×3​ $$SI = \frac{12,00,000}{100}$$SI=10012,00,000​ $$SI = ₹12,000$$SI=₹12,000

Step 2: Find Total Amount

$$A = P + SI$$A=P+SI $$A = 50,000 + 12,000$$A=50,000+12,000 $$A = ₹62,000$$A=₹62,000

✅ Answer:

• Simple Interest = ₹12,000
• Total Amount = ₹62,000

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🔎 Example 2: Finding Rate of Interest

Problem:

₹30,000 becomes ₹36,000 in 4 years under simple interest. Find the rate.

Step 1: Find SI

$$SI = A – P$$SI=A−P $$SI = 36,000 – 30,000$$SI=36,000−30,000 $$SI = ₹6,000$$SI=₹6,000

Step 2: Use SI Formula

$$SI = \frac{P \times R \times T}{100}$$SI=100P×R×T​ $$6,000 = \frac{30,000 \times R \times 4}{100}$$6,000=10030,000×R×4​ $$6,000 = 1,200R$$6,000=1,200R $$R = 5\%$$R=5%

✅ Answer:

Rate of Interest = 5% per annum

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🔹 Key Characteristics of Simple Interest

✔ Interest remains constant every year
✔ Easy to calculate
✔ Suitable for short-term financial decisions
✔ Does not consider time value compounding

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🔹 When to Use Simple Interest

• Short-term business loans
• Borrowing from individuals
• Treasury bills (basic calculations)
• Quick financial estimation
• School-level financial mathematics

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📌 Important Note

In long-term investments, Compound Interest gives higher returns because interest is earned on interest. Simple interest is mainly useful for straightforward and short-duration financial calculations.

1. “Garden Cities of To-Morrow”
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   • Year: 1898
   • Key Idea: Introduced the Garden City concept, advocating self-contained communities with greenbelts.
2. “The City in History”
   • Author: Lewis Mumford
   • Year: 1961
   • Key Idea: A historical analysis of urban development and planning.
3. “The Death and Life of Great American Cities”
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   • Year: 1961
   • Key Idea: Criticized modernist urban planning and emphasized vibrant, mixed-use neighborhoods.
4. “Urbanism as a Way of Life”
   • Author: Louis Wirth
   • Year: 1938
   • Key Idea: Explored how urbanization shapes social structures.
5. “The Image of the City”
   • Author: Kevin Lynch
   • Year: 1960
   • Key Idea: Introduced concepts like legibility and mental maps in city planning.

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Modern & Contemporary Planning Books

6. “A Theory of Good City Form”
   • Author: Kevin Lynch
   • Year: 1981
   • Key Idea: Developed a framework for evaluating urban design quality.
7. “Good City Form”
   • Author: Kevin Lynch
   • Year: 1984
   • Key Idea: Expanded on his earlier work on city imageability and planning.
8. “Cities of Tomorrow: An Intellectual History of Urban Planning and Design in the Twentieth Century”
   • Author: Peter Hall
   • Year: 1988
   • Key Idea: Analyzes urban planning theories and their real-world applications.
9. “The Just City”
   • Author: Susan S. Fainstein
   • Year: 2010
   • Key Idea: Advocates for social justice in urban planning.
10. “The Resilient City: How Modern Cities Recover from Disaster”

• Authors: Lawrence J. Vale & Thomas J. Campanella
• Year: 2005
• Key Idea: Examines how cities rebuild after disasters.

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Transportation & Sustainable Planning Books

11. “The High Cost of Free Parking”

• Author: Donald Shoup
• Year: 2005
• Key Idea: Discusses how excessive parking requirements harm urban areas.

12. “Transit-Oriented Development in the United States”

• Authors: Robert Cervero et al.
• Year: 2004
• Key Idea: Explores the benefits and design principles of Transit-Oriented Development (TOD).

13. “Walkable City: How Downtown Can Save America, One Step at a Time”

• Author: Jeff Speck
• Year: 2012
• Key Idea: Promotes walkability as key to successful urban planning.

14. “The Sustainable Urban Development Reader”

• Authors: Stephen Wheeler & Timothy Beatley
• Year: 2004
• Key Idea: A collection of important essays on sustainable urbanism.

15. “Cycling and Society”

• Authors: Dave Horton, Paul Rosen, Peter Cox
• Year: 2007
• Key Idea: Examines cycling’s role in urban transport and sustainability