Posted by tyler on .
While doing some interval training, a runner runs a distance interval at a pace of 4.00 m/s. She then runs the next interval at 4.500 m/s and the last interval at 5.500 m/s. Assuming each interval is exactly 125. m, what is her average speed for this workout?

physics 
Elena,
t1=s1/v1=125/4=31.25 s.
t2= s2/v2=125/4.5=27.78 s.
t3= s3/v3=125/5.5=22.73 s.
t=31.25 +27.78+22.73=81.76
v(ave) =total distance/ time taken = 125•3/81.76=4.59 m/s