Forces and equilibrium — practice question

A car with mass $1500\,\text{kg}$ is pulling a trailer of mass $m\,\text{kg}$ on a level straight road. The car and trailer are joined by a tow-bar that is horizontal, light and rigid. A resistance force of $F\,\text{N}$ acts on the car and a resistance force of $200\,\text{N}$ acts on the trailer. The engine of the car provides a driving force of $3200\,\text{N}$, the car accelerates at $1.25\,\text{m s}^{-2}$ and the tension in the tow-bar is $300\,\text{N}$.