# The remarkably easy puzzle that most uni students get wrong

IT may be ranked as the university with the best academic reputation in the world, but the majority of Harvard students are still flummoxed by a simple logic puzzle.

In fact, according to psychologist Daniel Kahneman's book Thinking Fast and Slow, more than half of students at leading universities struggle with it - and that figure rises to above 80 per cent at "less selective" institutions.

See how you get on:

• A bat and ball cost £1.10.
• The bat costs one pound more than the ball.
• How much does the ball cost?

## How much does the ball cost?

This poll ended on 01 October 2016.

## Current Results

5p

44%

10p

47%

15p

5%

Other

2%

This is not a scientific poll. The results reflect only the opinions of those who chose to participate.

As Kahneman explains:

"A number came to your mind. The number, of course, is 10: 10p. The distinctive mark of this easy puzzle is that it evokes an answer that is intuitive, appealing, and wrong. Do the math, and you will see. If the ball costs 10p, then the total cost will be £1.20 (10p for the ball and £1.10 for the bat), not £1.10. The correct answer is 5p. It is safe to assume that the intuitive answer also came to the mind of those who ended up with the correct number - they somehow managed to resist the intuition...

"Many people are overconfident, prone to place too much faith in their intuitions. They apparently find cognitive effort at least mildly unpleasant and avoid it as much as possible."