Answer :
Thank you for posting your question here at brainly. I hope the answer will help you. Feel free to ask more questions here.
Below is the solution:
30x+10x+5y+30y = 40x +35y
which means your cost function is C(x) = 40x+17640/x
then taking the derivative C'(x) = 40-17640x^-2
set that equal to zero and solve
x=21
so 504 = 21y
y =24
Below is the solution:
30x+10x+5y+30y = 40x +35y
which means your cost function is C(x) = 40x+17640/x
then taking the derivative C'(x) = 40-17640x^-2
set that equal to zero and solve
x=21
so 504 = 21y
y =24