A Woman is in a rowboat 3 km off shore at point W. In order to get to point B on shore 8 km downstream, she first rows from point W to point P and...

A Woman is in a rowboat 3 km off shore at point W. In order to get to point B on shore 8 km downstream, she first rows from point W to point P and then walks from point P to point B. If she rows at the rate of 3 km/hr and walks at the rate of 6 km/hr, where should she choose point P to minimise her time of travel? Recall that Distance=Rate/time or Time=Distance/Rate