The 'world's shortest IQ test' with just three questions but only a 17% pass rate
Despite the small number of questions, the Cognitive Reflection Test really challenges your brain.
Many of us like to put our intelligence to the test, whether that's to keep ourselves sharp or if we just enjoy proving our mettle. There are many ways to do this, from doing crosswords or brainteasers, to watching game shows or doing pub quizzes.
But one of the most common ways to do this is with an IQ test, which will pose different types of questions to get your brain working. However, these are often quite long and can take a big chunk out of your day.
So what if you could take on a challenge that is often thought to be the world's shortest IQ test? With just three questions, you'll be done in a few minutes and able to get on with your day.
But you shouldn't be fooled by the apparent simplicity, as each question poses its own particular problems and only 17 per cent of people were able to get full marks during a research study, The Mirror reports.
The mini quiz is called The Cognitive Reflection Test. It was originally part of a research paper published 20 years ago by Massachusetts Institute of Technology (MIT) Professor Shane Frederick.
Professor Frederick had over 3,000 people from a range of educational backgrounds complete the test for his study. And despite there being Ivy League students from Yale and Harvard taking part, the pass rate was less than one in five, with a whopping 83 per cent failing to get all three correct.
Speaking about the test, Professor Frederick, said: "The three items on the CRT are 'easy' in the sense that their solution is easily understood when explained, yet reaching the correct answer often requires the suppression of an erroneous answer that springs 'impulsively' to mind."
And it seems that intelligence testing, like fashion, may be cyclical, as the quiz has reappeared online in recent years, despite it being two decades since the 2005 paper was published.
Naturally, lots of people want to test their intelligence with this quick quiz. And if that sounds like you, then read on below to see if you can get 100 per cent on The Cognitive Reflection Test.
Questions
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 five machines five minutes to make five widgets, how long would it take 100 machines to make 100 widgets?
3. In a lake, there is a patch of lily pads. 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?
Answers
The three answers directly below are the most common responses from participant, however they are incorrect.
1. 10 cents
2. 100 minutes
3. 24 days
Professor Frederick said: "Anyone who reflects upon it for even a moment would recognise that the difference between $1 and 10 cents is only 90 cents, not $1 as the problem stipulates.
"In this case, catching that error is tantamount to solving the problem, since nearly everyone who does not respond '10 cents' does, in fact, give the correct response."
The correct answers are:
1. 5 cents
2. 5 minutes
3. 47 days
Do these answers make sense? If not then don't worry, as we explained you are far from alone. And, thankfully, the author of The Hoy of Game Theory: An Introduction to Strategic Thinking, Presh Talwalkar, has explained the working behind the answers on his blog, Mind Your Decisions.
He said: "[For question one] Say the ball costs X. Then the bat costs $1 more, so it is X + 1. So we have bat + ball = X + (X + 1) = 1.1 because together they cost $1.10. This means 2X + 1 = 1.1, then 2X = 0.1, so X = 0.05. This means the ball costs 5 cents and the bat costs $1.05.
"[For question two] If it takes 5 machines 5 minutes to make 5 widgets, then it takes 1 machine 5 minutes to make 1 widget (each machine is making a widget in 5 minutes). If we have 100 machines working together, then each can make a widget in 5 minutes. So there will be 100 widgets in 5 minutes.
"[For question three] Every day FORWARD the patch doubles in size. So every day BACKWARDS means the patch halves in size. So on day 47 the lake is half full."
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