After landing a job in Wall Street, you have to decide how to weather the sudden thunderstorms in New York. One solution is to buy now 20 low-quality umbrellas for $10 each from a street-vendor; they are useless after a thunderstorm, but this quantity is expected to get you through your first year. Another option is to buy a very elegant, "made in France" umbrella for $170 that will last you for 2 years. Finally, the famous Greek model "Uranus" is available; it is the most expensive one, priced at $245, but it lasts for 3 years. Having just graduated from college your credit score is not exactly stellar, so your discount rate is 30%. 1. Which umbrella model should you choose