A water supply maintains a constant rate of flow for water in a hose. You want to change the opening of the nozzle therefore that water leaving the nozzle reaches a height that is nine times the current maximum height the water reaches with the nozzle vertical. To do so, what must you do?
Decrease the area of the opening by a factor of 81
Decrease the area by a factor of 18
Decrease the area by a factor of 9
Decrease the area by a factor of 3
Give up because it cannot be done