To solve this problem, we can use a system of equations. Let the original salaries of Mahi and Chandu be

$$x$$ and

$$2x$$
According to the query, if the salary is increased by 4500, then we have:

$$\frac{x+4500}{2x+4500}=\frac{50}{67}$$

Solving the above equation, we get

$$67\cdot (x+4500)=50\cdot (2x+4500)$$

$$67\cdot x+67\cdot 4500=50\cdot 2x+50\cdot 4500$$

$$67x+301500=100x+22500$$

$$301500-22500=100x-67x$$

$$33x=76500$$

$$x=\frac{76500}{33}$$

$$x=2318.18$$

The original salary of Chandu was

$$2x=2\times 2318.18$$

$$=4636.36$$

Therefore, the original salary of Chandu was 4636.36