Esther Is a Swimmer Who Prides Herself in Having a Smooth

Short Answer

Esther is a swimmer who prides herself in having a smooth backstroke.Let s(t)be her position in an Olympic size (50-meter)pool, as a function of time (s(t)is measured in meters, t is seconds).Below we list some values of s(t)for a recent swim.Find Esther's average speed over the entire swim in meters per second.Round to 2 decimal places.
$$\begin{array} { c c c c c c c c c c c c } t & 0 & 3.0 & 8.6 & 14.64 & 21.35 & 28.06 & 32.33 & 39.04 & 46.36 & 54.9 & 61 \\s ( t ) & 0 & 10 & 20 & 30 & 40 & 50 & 40 & 30 & 20 & 10 & 0\end{array}$$