On an amount of ₹2,00,000, a bank gives ₹1,04,175 as interest in 3 years. If the interest is compounded annually, then what is the interest rate per annum?

Correct option is B

Given:
Principal (P) = ₹2,00,000
Compound Interest (CI) = ₹1,04,175
Time (n) = 3 years
Formula Used:
Amount (A) =  $$P + CI = P\left(1 + \frac{R}{100}\right)^{n}$$​​
Solution:
A = 200000 + 104175 = 304175.
​$$304175 = 200000\left(1 + \frac{R}{100}\right)^{3}\\ \ \\\frac{304175}{200000} = \left(1 + \frac{R}{100}\right)^{3}\\ \ \\\frac{12167}{8000} = (1 + \frac{R}{100})^{3}\\ \ \\(\frac{23}{20})^{3} = (1 + \frac{R}{100})^{3}\\ \ \\\frac{23}{20} = 1 + \frac{R}{100}\\ \ \\\frac{3}{20} = \frac{R}{100} \Rightarrow R = 15$$​​
So the correct answer is (b)