Initially, there are $3$ employees. & The project requires $40$ hrs. from each of $3$ employees to complete it.
So, the project requires a total of $40 \times 3\hspace{0.1cm} hr = 120\hspace{0.1cm} hrs$
then, the company hires a contractor.
Now, Total employees$ = 3 + 1 =4$
The total amount of work equally divides among the $4$ employees.
So, each employee has to work for $\dfrac{120}{4} = 30 \hspace{0.1cm}hrs$
Now, except the contractor, each employee is paid for $Rs.\hspace{0.1cm} 25/hr$.
So, except the contractor $3$ employees get a total of $90\times 25 = 2250\hspace{0.1cm} Rs$.
Now, the contractor gets a total of $30\times 10=300\hspace{0.1cm} Rs.$
$\color{green}{\text{To complete the project the company requires}}$ $\color{orange}{2250 + 300} = \color{red}{2550\hspace{0.1cm} rs.}$