A man starts his job with a certain monthly salary and earns a fixed increment every year. If his salary was Rs. 1500 after 4 year of service and Rs. 1800 after 10 years of service, what was his starting salary and what is the annual increment?

Explanation

To solve the problem step by step, we will define the variables and set up the equations based on the information given.

### Step 1: Define the Variables
Let:
- \( X \) = starting monthly salary (in Rs.)
- \( Y \) = annual increment (in Rs.)

### Step 2: Set Up the Equations
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