Puzzles & Quizzes

Try to Solve the Tricky Alien Extinction Riddle

The alien extinction riddle presented by Presh Talwalkar is for those up for a real challenge.

The Problem

This puzzle has supposedly been presented in technical job interviews. The problem goes as follows: One alien lands on Earth all by itself. Every day after that landing, each alien on Earth undergoes some sort of transformation, which could be any of these four equally likely events:

  • The alien dies
  • The alien does nothing
  • The alien replicates itself (2 aliens total)
  • The alien replicates itself twice (3 aliens total)

With bad luck, the alien species might die out quickly. But with better luck, the aliens could survive indefinitely. What is the probability the alien race eventually goes extinct? Scroll down to read the correct answer, or watch the video below to learn how this one is solved.

Can You Solve the Alien Extinction Riddle?

Supposedly, this question has been asked in technical job interviews.


The probability the alien race eventually dies out and goes extinct is 41.4%. To find out how to arrive at this answer, check out the video above.

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Written by Curiosity Staff October 16, 2016

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