The world’s shortest IQ test, also known as the Cognitive Reflection Test, was created by famous psychologist Shane Frederick in 2015. While traditional IQ tests consist of dozens of questions designed to quantify your intelligence, this test has only 3 questions, but it doesn’t mean it’s easy to pass this test.
Each question has a deceptively simple appearance but requires sharp critical thinking and a keen mind to answer correctly.
Only 17% of people can answer all the questions correctly, so if you manage to get all three right, you're among a small, elite group of individuals with exceptional cognitive reflection abilities!
Are you ready to see if you have what it takes?
The World’s Shortest IQ Test Questions
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?
2. If it takes 5 machines 5 minutes to make 5 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?
Correct Answers
Here are the answers to this short IQ test; let’s see how you did.
1. The correct answer is 5 cents.
What usually happens:
- About 20% of people get it right: 5 cents
- About 80% get it wrong: 10 cents
Many people quickly think the ball costs 10 cents. This seems to fit at first. But if you think more, you'll see that if the ball was 10 cents, the bat would be $1.10. That adds up to $1.20, which is too much.
Here is an easy way to calculate the answer using a bit of mathematical reasoning.. Since the bat costs $1 more than the ball, it can be expressed as (x + 100) cents. Together, their total cost is $1.10, so you can set up the equation x + (x + 100) = 110.
Solving this will give you the correct price of the ball:
- 2x + 100 = 110
- Subtract 100 from both sides:
- 2x = 10
- Divide both sides by 2:
- x = 5
So, the ball costs 5 cents, and the bat costs $1.05.
2. The correct answer is 5 minutes.
What usually happens:
- About 30% of people get it right: 5 minutes
- About 70% get it wrong: 100 minutes
Many people quickly think it would take 100 minutes. This seems to make sense at first. But it's not right because it doesn't think about how fast the machines work.
Let's break it down:
- 5 machines make 5 widgets in 5 minutes.
- This means each machine makes 1 widget in 5 minutes.
- So, 100 machines would make 100 widgets in 5 minutes too.
The key is to focus on how fast each machine works, not just the total number of machines or widgets.
3. The correct answer is 47 days.
What usually happens:
- About 20% of people get it right: 47 days
- About 80% get it wrong: 24 days
Many people quickly think it would take 24 days. This seems to make sense because it's half of 48 days. But it's not right.
Here's why:
- The lily pad doubles every day.
- On the last day (day 48), it goes from covering half the lake to the whole lake.
- This means it covered half the lake on day 47.
The tricky part is that the lily pad grows very fast at the end. It doesn't grow the same amount each day but instead doubles.
How Did You Do?
With only 3 questions, the CRT is not only the shortest IQ test, but it is also often dubbed the "world’s fastest IQ test." Did you get all three right? Then you likely have an above-average IQ.
While this test provides insight into specific aspects of problem-solving and logical reasoning, it's important to note that these questions represent only a small fraction of the skills and abilities that contribute to overall intelligence.
Want a more accurate and comprehensive assessment of your intellectual abilities?
Take our IQ test to gain deep insights into your cognitive strengths, identify areas for growth, and understand how your mind works across multiple dimensions of intelligence.
And here’s the good news: it will only take about 10 minutes!
