Use the following information to answer question 49-51.
The graph below shows a car's speed, s, in feet per second, versus time, t, in seconds.
51. The area under a speed-time graph between any 2 values of represents the distance traveled during that time interval. For this graph, the area between the s(t) graph and the t-axis represents the total distance traveled. At what time, t seconds. will the car have traveled half the total distance for these 16 seconds?