Try the world’s shortest IQ test: Just 3 questions

This test has been found to have a substantial correlation with cognitive ability and is potent predictor of performance on a wide sample of tasks.

3 question IQ test

The test:

Question 1:

A bat and a ball cost $1.10 in total. The bat costs $1.00 more than the ball. How much does the ball cost?

Question 2:

If it takes 5 machines 5 minutes to make 5 widgets, how long would it take 100 machines to make 100 widgets?

Question 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?



How did you do?

Well, before you consider how you did, let’s look at how some top American students performed in this test to give you a benchmark.

In a survey of 3,428 people, an astonishing 33 percent answered all questions incorrectly.

83 percent got at least one of the questions wrong.

Only 48 percent of MIT students were able to answer all three questions correctly.


What you probably answered:

Don’t worry, you’re not alone.

Question 1:

The ball costs $0.10

Question 2:

100 minutes

Question 3:

24 days


The correct answers

The correct answers are:

Question 1:

The ball costs $0.05

Question 2:

5 minutes

Question 3:

47 days



Harder than expected?

This test is known as the Cognitive Reflection Test (CRT). The test determines your brain’s ability to quickly realise that a problem is harder and more complex than it appears on the surface.

Here’s the great thing about this test–it has been found to correlate strongly with the best tests in the world to measure “general intelligence,” which consist of hundreds of questions and take hours to complete – so it’s known as one of the best and fastest ways to measure cognitive ability.