A man's pension on retirement from service is equal to half the average salary during last 3 years of his service. His salary from 1-1-1983 is Rs 380 per month with increment of Rs 40 due on 1-10-83, 1-10-84 and 1-10-85, If he retires on 1-1-86, what pension does he draw per month?

Options

A. Rs 205
B. Rs 215
C. Rs 225
D. Rs 230

Answer

To solve the problem step by step, we need to calculate the average salary of the man during the last three years of his service and then find out his pension based on that average salary.

### Step 1: Determine the salary for each period
1. **From 1-1-1983 to 1-10-1983 (9 months)**:
- Salary = Rs 380 per month
- Total salary for 9 months = 9 * 380 = Rs 3420

2. **From 1-10-1983 to 1-10-1984 (12 months)**:
- Salary = Rs 380 + Rs 40 = Rs 420 per month
- Total salary for 12 months = 12 * 420 = Rs 5040

3. **From 1-10-1984 to 1-10-1985 (12 months)**:
- Salary = Rs 420 + Rs 40 = Rs 460 per month
- Total salary for 12 months = 12 * 460 = Rs 5520

4. **From 1-10-1985 to 1-1-1986 (3 months)**:
- Salary = Rs 460 + Rs 40 = Rs 500 per month
- Total salary for 3 months = 3 * 500 = Rs 1500

### Step 2: Calculate the total salary for the last three years
Now, we sum up all the salaries calculated above:
- Total salary = Rs 3420 + Rs 5040 + Rs 5520 + Rs 1500
- Total salary = Rs 3420 + Rs 5040 = Rs 8460
- Total salary = Rs 8460 + Rs 5520 = Rs 13980
- Total salary = Rs 13980 + Rs 1500 = Rs 15480

### Step 3: Calculate the average salary
The average salary over the last 36 months (3 years) is calculated as follows:
- Average salary = Total salary / Number of months
- Average salary = Rs 15480 / 36
- Average salary = Rs 430

### Step 4: Calculate the pension
The pension is equal to half of the average salary:
- Pension = Average salary / 2
- Pension = Rs 430 / 2
- Pension = Rs 215

### Conclusion
The man’s pension on retirement is Rs 215 per month.