In the adjoining figure, AC + AB = 5 AD and AC - AD = 8. The area of the rectangle ABCD is:

In the adjoining figure, AC + AB = 5 AD and AC - AD = 8. The area of the rectangle ABCD is:

A square piece of cardboard of sides ten inches is taken and four equal square pieces are removed at the corners. The sides are then turned up to form an open box. Then the maximum volume such a box can have is