This is a calculus question. Please solve showing all steps

Question 849 Sam applies the brakes steadily to his car, which is travelling at 20 m/s. The position of the car (relative to where he started applying the brakes) t seconds after he begins to slow down is given by s(t) = 20t - 0.3t . How far did the car travel before it came to a stop? What was the deceleration of the car when it had travelled 37.6 m after applying the brakes? Round your final answers to the nearest tenth. Make sure to show all work for your calculation