IQ tests are a convenient and practical way to determine how smart you are.

Typically, the tests can be quite long, lasting over an hour with a variety of questions designed to test your brain to its limits. Despite this, many brains might be surprised to learn that there is an IQ test with just three questions.

However, the shortness of the test does not mean that it is less difficult. In fact, one study found that only 17% of participants were able to complete the puzzle. Known as the Cognitive Thinking Test, the quiz was originally part of a research paper published in 2005 by MIT professor Shane Frederick, reports the Mirror.

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Since resurfacing online, the diary has gone viral as people race to see if they can pass the ‘world’s shortest IQ test‘. As part of the study, Professor Frederick administered the IQ test to more than 3,000 participants from a variety of educational backgrounds.

Of this large group of people, only 17% managed to score three out of three on the test. Speaking of the test, Professor Frederick said: “The three elements of the CRT are ‘easy’ in the sense that their solution is easily understood when explained, but arriving at the correct answer often requires deleting a wrong answer. that ‘impulsively’ pops up in the mind.”

### What are the questions?

Read below to review the three questions included in the short IQ test:

1. A bat and a ball cost \$1.10 in total. The bat costs \$1 more than the ball. How much does the balloon cost?

2. If it takes five machines five minutes to make five widgets, how long would it take 100 machines to make 100 widgets?

3. In a lake, there is a patch of water lilies. Every day, the patch doubles in volume. If it takes 48 days for the plot to cover the entire lake, how long would it take for the plot to cover half of the lake?

Below are the three most common answers which are actually all Incorrect:

1. 10 cents

2. 100minutes

3. 24 days

Professor Frederick adds: “Anyone who thinks about it for a moment would recognize that the difference between \$1 and 10 cents is only 90 cents, not \$1 as the problem states.

“In this case, catching that error is like solving the problem, since almost everyone who doesn’t answer ’10 cents’ actually gives the correct answer.”

### What are the correct answers?

1. 5 cents

25 minutes

3. 47 days

If you’re still a bit confused by the answers even after reading them, an explanation of their equations has been provided by Presh Talwalkar, the author of The Hoy of Game Theory: AN Introduction to Strategic Thinking. He provided the following explanations for each solution:

1. Suppose the ball costs X. Then the bat costs \$1 more, so it is X + 1. So we have bat + ball = X + (X + 1) = 1.1 because together they cost \$1.10. This means 2X + 1 = 1.1, then 2X = 0.1, so X = 0.05. This means that the ball costs 5 cents and the bat costs \$1.05.

2. If it takes 5 minutes for 5 machines to create 5 widgets, it takes 5 minutes for 1 machine to create 1 widget (each machine makes a widget in 5 minutes). If we have 100 machines working together, each can create a widget in 5 minutes. So there will be 100 widgets in 5 minutes.

3. Each day, the FORWARD patch doubles in size. So every day BACKWARDS means the patch halves. Thus, on day 47, the lake is half full.