Salary for the 1st year = Rs. 8000
and according to the question,
There is an annual increment of Rs. 500
⇒ The salary for the 2nd year = Rs. 8000 + 500 = Rs.8500
Now, again there is an increment of Rs. 500
⇒ The salary for the 3rd year = Rs. 8500 +500 = Rs. 9000
Therefore, the series is
8000 , 8500 , 9000 , …
Difference between 2nd term and 1st term = 8500 – 8000 = 500
Difference between 3rd term and 2nd term = 9000 – 8500 = 500
Since, the difference is same.
Hence, salary in successive years are in AP with common difference d = 500 and first term a is 8000.