The man in the rowboat that is a = 4 miles from nearest point A on straight shoreline wants to reach the house located at the point B that is b = 7 miles farther down shoreline. He plans to row to the point P which is between A and B and is x miles from house, and then he will walk remainder of distance. Assume he can row at the rate of 3 mi/hr and can walk at the rate of 5 mi/hr. If T is total time required to reach house, state T as the function of x.