y rides a train along a straight north-south track. His position at timet in hour is s(t) = (–t¹ – 2t² - 4t+20) km north of Montre ge velocity between time t = 1 and t = 10 hour is

The traffic flow rate (cars per hour) across an intersection is r(t) = 200 + 1000t - 150t², where t is in hours, and t=0 is 6am. How many cars pass through the intersection between 6 am and 8 am? cars