Ramesh has Rs. 18,000. He deposited Rs. 7,000 in a bank at the rate of 5% per annum and Rs. 6,000 in other bank at the rate of 6% per annum simple interest. If he received Rs. 1,160 as simple interest at the end of one year, then the rate of interest per annum on rest of the capital is equal to:

Correct option is C

Given :
- Total capital = Rs. 18,000
- Amount deposited in Bank 1 = Rs. 7,000 at 5% per annum interest
- Amount deposited in Bank 2 = Rs. 6,000 at 6% per annum interest
- Simple interest received after 1 year = Rs. 1,160
- We need to find the rate of interest on the remaining amount.

Formula Used:
The formula for calculating simple interest is:

$$\text{Simple Interest} = \frac{P \times R \times T}{100}$$​
Where:
 P  is the principal amount,
 R is the rate of interest,
 T is the time period in years.

 Solution:

1. Interest from Bank 1:
$$\text{Interest from Bank 1} = \frac{7000 \times 5 \times 1}{100} = 350$$​
2. Interest from Bank 2:
$$\text{Interest from Bank 2} = \frac{6000 \times 6 \times 1}{100} = 360$$​
3. Total interest from both banks:
350 + 360 = 710
4. Remaining interest:
1160 - 710 = 450
5. Remaining capital:
18000 - (7000 + 6000) = 5000
6. Rate of interest on remaining capital:
​$$450 = \frac{5000 \times R}{100} \Rightarrow R = \frac{45000}{5000} = 9$$​​
Ans:9%