The equation is r(x) = 10x - 0.025x² where x is measured in thousands of toys produced, and r(x) is measured in thousands of dollars.
For maximum r, r'(x) = 0
It becomes: r'(x) =

=


x= 200
Hence, r(200) =

Solving it we get,
r(200) = 1000
Hence, maximum revenue is $1000.