A company determines that its marginal revenue (in dollars per day) is given by m the company's marginal cost (in dollars per day) is given by find the total profit from to (the first 6 days).

17 a tourist was planning a trip by car for travelling at some constant speed for 2.5 hours. however, he found that if he increases the speed by 20 km/h he can cover the same distance in 30 minutes less time than it was planned. what was the planned speed of the tourist, in km/h?