When difference between compound and simple interest for three years is Rs. 186 at 10% interest per annum, the principal is Rs. ______

Correct option is D

Given:

Difference between CI and SI = Rs. 186

Time (T) = 3 years

Rate (R) = 10% p.a.

Concept Used:

The difference between compound interest (CI) and simple interest (SI) for 3 years is:

Difference = $$\frac{P \times R^2 \times (300 + R)}{100^3}$$​​

Solution:

Applying the formula;

​$$186 = \frac{P \times 10^2 \times (300 + 10)}{100^3} \\ \ \\186 = \frac{P \times 100 \times 310}{1000000} \\ \ \\186 = \frac{P \times 31000}{1000000} \\ \ \\186 = \frac{P \times 31}{1000} \\ \ \\P = \frac{186 \times 1000}{31} = Rs. \, 6000$$​​