Short Math Test Asks 3 Questions, Many People Get Them Wrong

A quick math test with just three questions is popular online. It's called the Cognitive Reflection Test. Most people find it hard to answer all the questions right. It tests how we think.
By Newsroom | Education, Puzzles |

A brief test, presented as a measure of intelligence and patience, has surfaced across several online publications. Promoted as the "world's shortest IQ test," it comprises three mathematical problems. Reports indicate a low success rate, with a significant majority failing to answer all questions correctly. The test is often linked to research institutions, including MIT and Yale.

Only 20% of people can solve this three-question IQ test backed by MIT... are you one of them? - 1

Background of the Cognitive Reflection Test

The test, identified as a Cognitive Reflection Test (CRT), is attributed to research that assesses a person's tendency to rely on immediate intuition versus deliberate thought. It consists of three math-based questions designed to challenge initial, often incorrect, gut reactions. While some sources mention MIT and Yale professors in relation to the test, specific attribution details are varied. The claim is that accurately answering all questions signifies a higher level of cognitive processing.

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Only 20% of people can solve this three-question IQ test backed by MIT... are you one of them? - 2

Test Questions and Reported Difficulty

The CRT poses three specific problems. The exact wording and numbers can vary slightly across reports, but the core questions are consistent:

Only 20% of people can solve this three-question IQ test backed by MIT... are you one of them? - 3

  • Question 1 (Bat and Ball): This problem involves the cost of two items, a bat and a ball, with a given total price and a difference in their individual costs. One version states: "The bat costs $1.50, the ball costs $.50. How much does the ball cost?"

  • Question 2 (Widget Production): This question explores a rate of production. A common phrasing is: "If it takes five machines five minutes to make five widgets, how long would it take 100 machines to make 100 widgets?"

  • Question 3 (Lily Pads): This question, often the most challenging to grasp intuitively, describes a doubling phenomenon in a lake. One version reads: "In a lake, there is a patch of lily pads. Every day, the patch doubles in size." The question that follows is typically "How much does the ball cost?" or a variation thereof, referencing the bat and ball problem, or a separate question about the lily pads themselves. However, one report links this question to the lily pads doubling.

Reported Success Rates and Comparisons

The publications consistently highlight a low percentage of individuals who solve all three questions correctly.

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Only 20% of people can solve this three-question IQ test backed by MIT... are you one of them? - 4

  • One report states that 17 percent of people got all three questions right, while 33 percent got all three wrong.

  • Another suggests that just 20 percent of people can solve the test.

  • Within academic settings, specific figures are cited:

  • 20 percent of Harvard University students answered all questions correctly.

  • 26 percent of Princeton University students succeeded.

  • 48 percent of MIT students got all three answers correct.

  • It is claimed that over 80 percent of the population fails to answer all questions correctly.

Analysis of Common Errors

The reports suggest that incorrect answers stem from intuitive, but flawed, reasoning.

  • Bat and Ball: The intuitive answer for the ball's cost might be $0.50, but the problem's setup requires a different calculation.

  • Widget Production: A common mistake is to assume a direct proportion, leading to an answer of 100 minutes. The intended logic focuses on the time per machine.

  • Lily Pads: The rapid growth when doubling each day is often underestimated, leading to difficulty in predicting the time to fill the lake if a future state is implied.

Academic Context and Test Purpose

The Cognitive Reflection Test is described as a tool to measure a person's ability to override instinctive responses and engage in more analytical thinking. The success of students at different universities suggests varying levels of innate analytical ability or training in approaching such problems. The test's brevity is a key feature, allowing for quick assessment.

Findings and Implications

The widespread reporting of this three-question test indicates a public interest in accessible measures of cognitive ability. The low success rates across various groups, including university students, suggest that reliance on intuitive thinking is common. The test's design challenges individuals to pause and engage in deliberate reasoning, a skill that may be more critical than often assumed. The variations in question phrasing across sources could introduce minor ambiguities, but the core challenge remains consistent.

Sources

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Frequently Asked Questions

Q: What is this short test?
It is a math test with three questions called the Cognitive Reflection Test. It is meant to see how well people think before they answer.
Q: Why is it hard?
The questions seem easy, but the first answer that comes to mind is often wrong. You have to think carefully.
Q: Who made this test?
Some reports say professors from places like MIT and Yale helped create it or similar tests.
Q: How many people get it right?
Most reports say that only about 20% of people get all three questions correct.