THE COMPLETE ARCHIVE9 puzzles · no spoilers
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3 puzzles · Conditional probability
Clear filtersA boy born on Tuesday
Choose a family uniformly from all two-child families, then keep only families with at least one boy born on a Tuesday.
Conditional probabilityMedium
At least one boy
A two-child family is selected uniformly, then filtered to keep only families with at least one boy.
Conditional probabilityEasy
The door you did not choose
Three doors hide one prize. You choose a door. A host who knows the prize location opens another door with no prize, then offers you the remaining closed door.
Conditional probabilityEasy