Copper was first discovered in 1870 in a town called Cobar. BPH resources currently own an unused copper mine in Cobar that was shut down four years ago due to the depressed price of copper. However, due to the recent resources boom, BPH are considering re-opening the mine.

Company management forecast that it would cost $100,000 to re-open the mine and they would extract 100,000 pounds of copper per year for three years if the mine was re-opened. After that time the deposit will be exhausted.  The current copper price is $4 per pound and it costs $3.60 per pound to extract. Each year the price is equally likely to rise or fall by $0.50 from its level at the start of the year. Assuming a discount rate of 10% should BPH open the mine now or should they wait one year to see if the price of copper rises?

请问老师和各位朋友，这题应该怎么做？

谢谢

假设这个数据$3.60 per pound的成本是保持不变的，假设开采的矿是年末出售，用二叉树的方法分析，计算出每一个年末的期望价格，那么第一年的期望价格是＝（3.5+4.5）/2=4，第二年年末的期望价格是：5*0.25+4*0.5+3*0.25=4, 第三年末的价格应该也为4， 在进行普通的NPV分析就可以了。