Correct Answer – Option 3 : Rs. 5600

Given:

The compound interest on an amount invested for 2 years at 12% per annum is Rs. 2544.

Formula:

CI = P [1 + (r/100)]ⁿ – P, when the rate of interest is r and the amount is invested for n years.

SI = PRT/100

Calculation:

Let the sum be Rs. P.

2544 = P [1 + (12/100)]² – P

P = 10000

Now, simple interest on Rs. 10,000

SI = (10000 × 7 × 8)/100

⇒ Rs. 5600

∴ The simple interest is Rs. 5600

Correct Answer – Option 3 : 240

Given:

The compound interest on an amount invested for 2 years at 15% per annum is Rs. 387.

Formula Used:

CI = P × (1 + r/100)ⁿ – P, where the rate of interest is r and the amount P is invested for n years.

SI = principal × rate × time/100 = Prt/100

Calculation:

Let the sum be Rs. P.

⇒ 387 = P (1 + 15/100)² – P

⇒ P = 1200

Now SI for 4 years at 5% simple interest rate = 1200 × 4 × 5/100 = 240 (in Rs.)

∴ Required simple interest is Rs. 240