Given,
The function for the profit is,
Differentiating the function with respect to x then,
Check for maximum by second order differentiation,
Differentiating the function with respect to x then,
Negative sign shows the maximum.
For maximum, taking dy/dx=0 then,
Subsituing the value of x in the function then,
Hence, 75 admissions counselors should the college employ to maximize its profit.