A Psychologist Created a 3-Question Test That Can Show Your Intellect Level Within a Minute

In 2005, a psychologist Shane Frederick created the shortest test for evaluating intellect. It has only 3 questions that you need to answer as quickly as possible. You can even check the answers yourself!

Bright Side invites you to take the test and check your cognitive abilities right away. Think a bit, write down your answers, and compare them with the right ones.


1. A tennis racket and a ball cost 1 dollar and 10 cents together. The tennis racket is 1 dollar more expensive than the ball. How much does the ball cost?

2. 5 machines produce 5 details within 5 minutes. How many minutes will it take for 100 machines to produce 100 details?

3. There are water lilies growing in a pond. They grow quite fast doubling the distribution area each day. It will take them 48 days to cover the pond fully. How many days do water lilies need to cover half of the pond?

Shane Frederick is a professor at the Yale School of Management. He specializes in research about how people make decisions and choices. He has even worked together with a Nobel prizewinner, Daniel Kahneman. Together with his team, Frederick has surveyed about 1,000 people who consisted partly of students of large American universities.

Besides testing these people for their cognitive abilities, the scientists also asked them about one more thing. Those interviewed were offered $3,400 now or $3,800 in a month.

As it turned out, most people who got a low score in the test didn’t agree to wait and preferred to get a smaller amount instantly. Conversely, people with high results in testing demonstrated the strong willpower that helped them to get a better remuneration.

The idea of the test is that wrong answers come to mind first: 100 cents, 100 minutes, 24 days. These answers are most often given by people with an intuitive mindset, while the ones with a more rational type of thinking give better answers on average.


1. The answer is 5 cents. If the ball cost 10 cents, the racket would cost 1 dollar and 10 cents while that’s how much both items cost together.

2. The answer is 5 minutes. The number of machines doesn’t influence the amount of time needed for producing one detail.

3. The answer is 47 days, not 24. If the amount of water lilies is doubling every day and the amount of days needed for covering the pond completely is 48, it’s logical that the lilies will cover half of the pond one day before it.

Did you manage to answer these questions correctly the first time? Please share your results with us in the comments!

Preview photo credit Gifted / FilmNation Entertainment