Question

find the rate of change of C with respect to P: C(p)=1100p/140-p

Answer 1

Just compute the derivative!!

Answer 2

C(p)=f(x)/g(x)
C'(p)=[g(x)f'(x)-f(x)g'(x)] / g(x)²
This is what you'll find if you carry out the operation based on the definition of a derivative... the quotient rule (or something like that).

Answer 3

yes and f(x) = 100p, g(x) = 140-p, substitute like u said and simplify!