A pond has frogs and crickets. Frogs eat crickets, so the number of frogs f is a function of the number of crickets c and is modeled by f(c) = 2c+8 frogs. The cricket population after t years can be modeled by c(t). After 2 years, there are 300 crickets, and the number of crickets is increasing by 20 crickets per year.

What is df/dt \t=2 ?