Only 17% of people can answer the world’s shortest IQ test correctly


  • A question in three logical evaluation is considered the shortest IQ test in the world.
  • The faster you answer the question, the higher your IQ.
  • Only 17% of people got a perfect score.

The Cognitive Reflection Test (CRT) has been hailed as the world’s shortest IQ test. Apparently, it only takes three questions to separate the Einsteins from the Homer Simpsons in this world.

The quiz, developed at Princeton in 2005 by psychologist Shane Frederick, is designed to test your ability to ignore your gut response and think slower and more rationally. Or in psychological terms, how good are you at ignoring System 1 (intuition) thinking in favor of System 2 (analytical) thinking? To be successful at CRT, you need to spend time thinking about your answer and questioning your intuitive answer.

Of course, to prove your genius you have to answer all three questions correctly, but speed matters too. Faster responses are another sign of a higher IQ.

So how smart are you really? Keep in mind that the questions may not be as simple as they seem at first glance. Even students at some of the best universities in the world (including Yale and Harvard) failed to get all three correct answers in one 2003 study. In fact, only 17% got a perfect score.

The quiz

1. A bat and a ball cost $ 1.10 in total. The bat costs $ 1 more than the ball. How much does the ball cost?

2. If it takes 5 machines 5 minutes to create 5 widgets, how long would it take 100 machines to create 100 widgets?

3. In a lake, there is a square of water lilies. Every day, the patch doubles in size. If it takes 48 days for the patch to cover the entire lake, how long would it take for the patch to cover half of the lake?

Scroll down for the answers!

The answers

  1. $ 0.05 – Chances are, you guessed $ 0.10. The answer is actually a little less – a $ 0.05 ball plus a bat costing $ 1.05 will set you back $ 1.10. And, of course, $ 1.05 is exactly $ 1 more than $ 0.05. (A Princeton Study found that those who answered $ 0.10 were “significantly” less patient than those who got the correct answer.)
  2. 5 minutes – Your instinct might be to say 100 minutes. Fortunately, it wouldn’t take that long. From the question, we can determine that it takes exactly 5 minutes for 1 widget machine to create 1 widget. Therefore, it would take 5 minutes to create 100 widgets from 100 widget machines.
  3. 47 days – You may have guessed 24 days. It seems intuitive to halve the number of days because you are halving the size of the water lily patch. But if the area of ​​the lake covered with water lilies doubles every day, it would only take a day to go from half covered to full. Take a day out of 48 days and you have 47 left.


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