A Girl Is on the Bank of a River That

Multiple Choice

A girl is on the bank of a river that is 1 kilometre wide. She wants to travel to a town on the opposite bank but 1 kilometre upstream. She intends to row in a straight line to some point P on the opposite bank and walk the remaining distance along the (straight) bank. To what point should she row in order to reach her destination in the least possible time if she can walk 5 kilometres per hour and row 3 kilometres per hour?Refer to the figure below:

A) x = 0 km (row directly to town)
B) x =1 km
C) x = km
D) x = km
E) x = km