The document discusses the economic problem of water scarcity in Australia and how markets attempt to solve this problem. It explains that water is a scarce resource in Australia, especially in the Murray-Darling Basin. This creates an economic problem and opportunity costs as choices must be made on how to allocate the limited water. The role of markets is then discussed, where the price of water is determined by the interaction of supply and demand. Markets can help solve the economic problem of scarcity by efficiently allocating the scarce water resource.