📘 Simple Interest

Basic Terms

Principal (P): Initial amount
Rate (R): Rate of interest per year
Time (T): Time period in years

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Simple Interest Formula

\[ \text{Simple Interest (SI)} = \frac{P \times R \times T}{100} \]

\[ \text{Amount (A)} = P + \text{SI} \]

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Finding P, R and T

\[ P = \frac{100 \times \text{SI}}{R \times T} \]

\[ R = \frac{100 \times \text{SI}}{P \times T} \]

\[ T = \frac{100 \times \text{SI}}{P \times R} \]

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🔥 Exam Shortcuts & Tricks

Shortcut 1:
If interest is same every year → it is Simple Interest

Shortcut 2:
SI for 1 year = \(\frac{P \times R}{100}\)

Shortcut 3:
Total SI for \(T\) years = (SI for 1 year) × \(T\)

Shortcut 4:
If SI equals principal, then \[ T = \frac{100}{R} \]

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📘 Solved Examples

Example 1:
Find SI on ₹1000 at 10\% per annum for 2 years. \[ \text{SI} = \frac{1000 \times 10 \times 2}{100} = 200 \]

Example 2:
Find the amount after 3 years at 5\% p.a. on ₹2000. \[ \text{SI} = \frac{2000 \times 5 \times 3}{100} = 300 \] \[ \text{Amount} = 2000 + 300 = 2300 \]

Example 3:
SI is ₹400 on ₹2000 in 2 years. Find rate. \[ R = \frac{100 \times 400}{2000 \times 2} = 10\% \]

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