7. A boat is sailing parallel to the shore at a rate ot 20 mph with a constant distance of 2 mi from the shore. It a lighthouse is a fixed point on the shore, at what rate is the distance between the boat and the lighthouse changing when the boat is 3.5 mi from the lighthouse? B. The graph below shows the velocity of an object over a 20-second interval. Find the total distance travelled by the object in those 20 seconds