Question

5. (This problem, due to Steven Strogatz, appeared in the New York Times.) Before going on vacation for a week, you ask your spacey friend to water your ailing plant. Without water, the plant has a 90% chance of dying. Even with proper watering, it has a 20% chance of dying. The probability that your friend will forget to water it is 20%. (a) What's the chance your plant will survive the week? (b) If your friend forgot to water it, what's the chance it'll be dead when you return? (e) If it's dead when you return, what's the chance that your friend forgot to water it?

Answer 1