An IQ test that asks just three questions has gone viral after the 2005 quiz resurfaced online. But it seems that while the test is short, it’s also tricky, and only about 17% of people passed a study.

There are several ways to put your intelligence to the test, one of the most common being the IQ test. However, while you would expect a long list of questions to establish a score, this test only asks for three.

If you imagine yourself as an academic, we’ve included the questions, and of course the answers and how it works, below. With 83% of respondents in the study not getting three out of three answers correct, don’t be too disappointed if you don’t get all the answers.

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Called the Cognitive Thinking Test, the quiz was originally part of a research paper published in 2005 by MIT professor Shane Frederick. This document recently resurfaced online and the Mirror reported that it had gone viral.

As part of his research, Professor Frederick administered the test to more than 3,000 participants from a variety of educational backgrounds – and even those who attended top US universities such as Yale and Harvard struggled to find all the answers.

Professor Frederick said: “The three elements of CRT are ‘easy’ in the sense that their solution is easily understood when explained, but arriving at the correct answer often requires removing a wrong answer that comes ‘impulsively’ “in mind.”

### The three questions

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?

### Three of the most common answers – 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 this error is like solving the problem, since almost everyone who doesn’t answer ’10 cents’ actually gives the correct answer.”

### The correct answers

1. 5 cents

25 minutes

3. 47 days

### And how they are made

Still perplexed by all this? Fortunately, Presh Talwalkar, the author of The Hoy of Game Theory: An Introduction to Strategic Thinking, explained how to find the right answers on his blog, Mind Your Decisions.

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.