Both subsoil and topsoil need to be added to a garden bed. One bag of subsoil requires 10 units of water to hydrate while one bag of topsoil requires 6 units of water to hydrate every day. The truck used to transport the dirt has limited capacity and therefore, the farmer has available 150 bags of topsoil and subsoil combined. In addition, at least 10 bags of topsoil must be used. Since the topsoil is more expensive, at most 30% of all bags of soil can be topsoil. How many bags of each should be bought to minimize the total amount of water required to hydrate the garden bed?