Given,
The function for the profit is,
![y=-10x^2+1500x-35000](https://img.qammunity.org/2023/formulas/mathematics/college/s3kcly7p4rq5wupduaoxwjosos79v5zneg.png)
Differentiating the function with respect to x then,
![\begin{gathered} (dy)/(dx)=(d)/(dx)(-10x^2+1500x-35000) \\ =-20x+1500 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/d9dxrqx5gehbp17nd6g4rh33owyul4khej.png)
Check for maximum by second order differentiation,
Differentiating the function with respect to x then,
![\begin{gathered} (d^2y)/(dx^2)=(d)/(dx)(-20x^{}+1500) \\ =-20 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/y4cwryxz599u3267nahfg0agwgz4q997fh.png)
Negative sign shows the maximum.
For maximum, taking dy/dx=0 then,
![\begin{gathered} -20x+1500=0 \\ 1500=20x \\ x=75 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/eoxuljowy0ny2v43kan6javtv308regbhh.png)
Subsituing the value of x in the function then,
![\begin{gathered} y=-10(75)^2+1500*75-35000 \\ =-56250+112500-35000 \\ =21250 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/6cjl8a47xdaf1gstrjol9ihybc6ta15vmy.png)
Hence, 75 admissions counselors should the college employ to maximize its profit.