(c) Force produced by the engine $F = \frac{P}{v} = \frac{30 \times 10^{3}}{30} = 10^{3}N$
Acceleration = $\frac{Forward\ force\ by\ engine\ - \ resistive\ force}{mas\ of\ car}$
$= \frac{1000 - 750}{1250} = \frac{250}{1250} = \frac{1}{5}\ m/s^{2}$