Vijay invests a sum of Rs. 5400 and Mohan invests a sum of Rs. 9400 at the same rate of simple interest per annum. If, at the end of 4 years, Mohan gets Rs. 360 more interest than Vijay, then find the rate of interest per annum (in percentage).

Correct option is B

Given:
Principal of Vijay (P₁) = Rs. 5400
Principal of Mohan (P₂) = Rs. 9400
Time (T) = 4 years
Difference in Interest = Rs. 360
Formula Used:
Simple Interest (SI) = (P × R × T) / 100
Solution:
Let the rate of interest be R%.
Interest by Mohan - Interest by Vijay = Rs. 360
​$$\Rightarrow \frac{9400 \times R \times 4}{100} - \frac{5400 \times R \times 4}{100} = 360\\\Rightarrow \left( \frac{R \times 4}{100} \right) \times (9400 - 5400) = 360\\\Rightarrow \left( \frac{R \times 4}{100} \right) \times 4000 = 360\\\Rightarrow \frac{R \times 16000}{100} = 360\\\Rightarrow 160R = 360\\\Rightarrow R = \frac{360}{160} = 2.25\\$$​​
Therefore, the rate of interest per annum is 2.25%.