The guy above is wrong. s=d/t true but your speed 1.5m/s =m/8s, D= 12m and her speed 2.0m/s=m/4s m=8m, 1.0m/s=m/4s= 4m. . . 8m+4m=12m you both walked the same distance, the only difference was she sped up .5m/s more in the first 4 seconds and then down 1.0m/s the last 4sseconds.