In order for a motorized dinghy to travel 3 mi upriver and then return in a total of 4 hr, how fast must the boat be able to travel in still water? 11. Memory Board. A computer-parts company wants to make a rectangular memory board that has a perimeter of 28 cm. What dimensions will allow the board to have a maximum area? 12. Hang Time. Use the function V T 48T 2. Anfernee Hardaway of the New York Knicks has a vertical leap of 36 in. What is his hang time?