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Price a Sequential Four-Box Search Game

WorldquantData Scientist · Technical Screen

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Four boxes contain one \$100 prize. Explain the assumptions and derivation clearly, check edge cases, and show how the result changes when those assumptions no longer hold.

Price a Sequential Four-Box Search Game

Four boxes contain one $100 prize. Each opening costs the same fee x; you choose an unopened box and may stop after any failure. Find the largest x for which starting optimally has nonnegative expected value. Then, after deriving that break-even fee, decide whether a player who paid that fee for the first opening and failed should continue.

Constraints & Assumptions

  • The prize is equally likely in each box.
  • Each additional opening costs x.

Clarifying Questions to Ask

  • Should the continuation decision compare only future conditional value and future costs?
  • Does finding the prize end the game immediately?

Follow-up questions

  • How does the answer generalize to `m` boxes?
  • What if unopened boxes have unequal probabilities?