+35 Megha has two large cylindrical urns for water, one of which is twice as deep as the other (note that the urns don't necessarily have the same base radius). Initially, the deep urn is full and the shallow urn is empty. At some time in the morning, Megha simultaneously beings draining the deep urn and filling the shallow urn at constant rates (though the two rates are not necessarily equal). At midday, the depth of the water in the two urns is equal. Megha finishes draining the deep urn at 1:00 pm and finishes filling the shallow urn at 10:00 pm. How many hours before midday did she start draining and filling the urns?
