Nirmal invests a sum of Rs. 5400 and Rakesh invests a sum of Rs. 9400 at the same rate of simple interest per annum. If, at the end of 5 years, Rakesh gets Rs. 360 more interest than Nirmal, then find the rate of interest per annum (in percentage).

Correct option is C

Given:

Nirmal's investment = Rs. 5400

Rakesh's investment = Rs. 9400

Difference in interest after 5 years = Rs. 360

Formula Used:

SI = $$\frac{P \times R \times T}{100}$$​​

Where:

P = Principal, R = Rate of interest, T = Time in years

Solution: 

After 5 year ;

SI(Rakesh) - SI(Nirmal)  = 360 

​$$\frac{9400 \times R \times 5}{100} - \frac{5400 \times R \times 5}{100} = 360 \\ \ \\470R - 270R = 360 \\ \ \\ 200R = 360 \\ \ \\R = \frac{360}{200} = 1.8\%$$​​

Thus, the rate of interest per annum is 1.8%