Inspired by the Fiddler on the Proof (formerly The Riddler), X’s Puzzle Corner aims to produce a weekly puzzle for readers that enjoy math, probability, and algorithms. Please submit your solution! Solutions will be accepted until 11 pm the following Sunday after the puzzle is posted (in this case 10/20/24). While it isn’t required, I encourage you to opt to have your solution shared so that we all get the chance to see how others thought about and attempted the problem!
The answers of all those that volunteered their solutions will be posted around Wednesday at 10 am.
In many cases, I expect the readers will be better puzzlers than me so I make no guarantees the solutions are correct. I also make no promises about having worked out the solutions to the puzzles ahead of time so it may be the case that they’re very challenging. Part of the fun is finding out!
Recall from Part 1 that:
You decide you want to make your fortune off the stock market. So far you’ve had mixed results but today is your lucky day; you happen to be sitting next a prolific investor, we’ll call him Warren. Warren tells you that the secret to his success are two mystical oracles given to him by some old dead guy named Ben. What’s more, Warren is about to retire and is willing to give you these oracles if you can prove you’re worthy of wielding them.
The first oracle is able to tell with certainty whether a stock will go up or down that day. The second oracle is able to tell you with certainty whether a stock will go up that hour. The question you are presented with is; which oracle can get you better returns and by exactly how much?
Consider the following stock behavior:
The stock’s value will change by a factor of (1+δ) from it’s pervious value each hour where δ is uniformly distributed from [-1/100, 1/100]. For example, after two hours, the value would be p_0 * δ_1 * δ_2. Note: these values are slightly different from Part 2.
The question for this week is, what’s the average difference in performance between an oracle that can predict whether the stock will go up each hour vs the oracle that can predict whether the stock will go up each day? The oracles are to perform over 5 days, 7 hours each day.
Good luck solving!
Please submit your answers here.