The world’s shortest IQ test is proving to be quite tough, with only 17 percent of respondents answering correctly. But how hard can it be when there are only three questions?

Created by MIT professor Shane Frederick back in 2005, the Cognitive Reflection Test has resurfaced recently. Despite the length, more than 80 percent of takers fail to score 3 out of 3.

Here are the three questions . . .



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


2.  It takes five machines five minutes to make five widgets.  How long would it take 100 machines to make 100 widgets?


3.  There’s a patch of lily pads in a lake.  Every day, the patch doubles in size.  If it takes 48 days for the patch to cover the entire lake, how long will it take to cover half of the lake?



And the answers . . .



1.  The common wrong answer is 10 cents.  The right answer is 5 cents.


2.  The common wrong answer is 100 minutes.  The right answer is 5 minutes.


3.  The common wrong answer is 24 days.  The right answer is 47 days.

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