TL;DR
The Monty Hall Problem: A canonical quantitative trading interview question at foundation difficulty. Commonly asked at Jane Street, Two Sigma, DE Shaw, Citadel.
By Valenke Exam Prep Team·Last updated 2026-06-01
foundationConditional Probability & Bayes
The Monty Hall Problem
Asked at: Jane Street, Two Sigma, DE Shaw, Citadel
Problem
You are on a game show. There are three doors: behind one is a car, behind the other two are goats. You pick Door 1. The host, who knows what is behind each door, opens Door 3 to reveal a goat. He then asks: "Do you want to switch to Door 2?"
Should you switch? What is the probability of winning if you switch versus if you stay?
Related concepts
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