Examoogle • User • info@examoogle.com • EE-2024-8821

Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked

MathematicsSimple & Compound Interest

If the simple interest on a sum of money for 3 years at 5% per annum is Rs 1,500, what is the principal?

Rs 8,000

Rs 10,000

Rs 12,000

Rs 9,000

Correct Answer

📐 MA • Math Direct FormulaMathematicsSimple & Compound Interest

Option B

Rs 10,000

Quick Summary:

Calculate the effective percentage: $3 \times 5 = 15\%$ . Since $15\%$ of Principal = $1500$ , $1\%$ = $100$ , so $100\%$ = $10000$ .

📐MAMath SolutionDirect Formula

📋 Given

Simple Interest (SI) = Rs 1,500, Time (T) = 3 years, Rate (R) = 5% per annum.

🔢 Formula Used

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

⚡ Exam Hall Shortcut / Speed Trick

Calculate the effective percentage: $3 \times 5 = 15\%$ . Since $15\%$ of Principal = $1500$ , $1\%$ = $100$ , so $100\%$ = $10000$ .

⚠️ Common Student Trap / Pitfall

Students often multiply by the rate instead of dividing, or confuse Simple Interest with Compound Interest formula.

📊 Diagram / Illustration

🔢 Step-by-Step Solution

Identify given variables

We are given the simple interest $SI = 1500$ , time $T = 3$ , and rate $R = 5$ .

SI=1500,T=3,R=5SI = 1500, T = 3, R = 5SI=1500,T=3,R=5

State the standard SI formula

The formula for simple interest is $SI = \frac{P \times R \times T}{100}$ . Rearranging to find the principal $P$ :

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

Substitute and Calculate

Substituting the known values: $P = \frac{1500 \times 100}{5 \times 3} = \frac{150000}{15}$ .

P=10000P = 10000P=10000

✅

B is correct because the calculated principal using the formula is Rs 10,000.

Core Concepts Used

Click any tag to open in AI Tutor

💡 EXAM TIP

This direct approach is the foundation for Profit and Loss questions, where the principal behaves like a Cost Price.

Loading discussion...