You are thinking about updating your laptop. For the old laptop, next year maintenance will cost $400, and these costs will double each year. The old machine could be sold today for $1,000 but resale value will decline 50% per year. A new laptop model costs $3,000, lasts for 3 years and costs $300/year to maintain. After 3 years the new model could be sold for $1,200. Revenue from your Laptop work is about $2500 annually. If r = 10% and we ignore taxes; should you replace the old laptop? If so, when should you do it