The Dowager Countess of Downton Abbey (who is somehow aware of the metric system) wishes to have a rectangular garden with area 30000 square meters. The garden will be enclosed by a garden wall on three sides. The fourth side of the garden will have no wall, as it is bordered by a straight section of a beautiful river. She wishes the enclosure to be completed as soon as possible. The quickest way to complete the project is to minimize the total length of the garden's wall. a Find y and y that minimize the length of the wall, subject to the condition that the area is 30000 square meters. ] river (no wall here)