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!

(h/t: brightside)

### Questions

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.