Below is the position-time graphs of two swimmers (A and B), swimming in a pool along a straight line. Both the swimmers start from two different positions 350 300 250- 200 150- 100+ 30+ Swimmer B Swimmer A -30- -100 20 30 40 50 60 70 80 Time(s) (a) Use the graph to predict when and where swimmer B passes swimmer A. (b) Estimate the speed of each swimmer at the point when B passes A (c) Which swimmer has the highest average speed? Explain your answer