Christopher Robin pulls a wagon (containing Pooh-Bear) in a straight line. In the first second his average speed is 0 ft/sec in the second it is 3 ft/sec, in the third it is 4 ft/sec, in the forth it is 3 ft/sec, in the fifth it is 2 ft/sec and in the sixth it is 1 ft/sec. Estimate the distance they have traveled in the 6 seconds. Is this the exact distance traveled