If \(f(c)=\frac{3}{2c-3}\), find \(\frac{kn^2}{lm}\) when \(f^{-1}(c)\times c \times f(c)\) equals the simplified fraction \(\frac{kc+l}{mc+n}\), where \(k,l,m\) and \(n\) are integers.
kn^2/lm = 15.
