A geologist has identified a surface vein of copper, the rights to which have been sold to Cannecon Copper. As the ore lies on the surface, the cost function depends only on the rate of extraction: yl C Y = ' ( I) 4 where Yt represents amount extracted in period 't = 0, 1, 2...' The price of copper ore in the world market has just risen from $100/unit to $1501unit, and is expected to remain $150/unit for the foreseeable future. Thus, the prot each period is .(K)=150-K-% According to the best information available from geological surveys, the vein (deposit) contains 120 units of recoverable copper ore. Cannecon's managers have created a short-term asset portfolio that returns 5% per annum. During how many periods will Cannecon extract from this vein of ore? \f