IQ stands for intelligence quotient and is used to generally measure intelligence. And the cognitive reflection test does just that.

The cognitive intelligence test comes from the paper ‘Cognitive Reflection and Decision Making,’ by Shane Frederick. Perhaps the most interesting aspect of this study is how simply it seemingly is. Well, at first glance. However, when you get down to answering the test, it is much more complicated than it seems.

Out of 3,428 people, 33% missed all three questions. And 83% of those missed at least one. Only 48% of MIT students were able to answer all of the questions correctly. Glance at them, calculate your answers, and then compare them to the correct answer.

(1) A bat and a ball cost $1.10 in total. The bat costs $1.00 more than the ball. How much does the ball cost? _____ cents

(2) If it takes 5 machines 5 minutes to make 5 widgets, how long would it take 100 machines to make 100 widgets? _____ minutes

(3) In a lake, there is a patch of lily pads. Every day, the patch doubles in size. If it takes 48 days for the patch to cover the entire lake, how long would it take for the patch to cover half of the lake? _____ days

What answers did you come up with? Here are the correct answers:

(1) 5 cents (not 10)
(2) 5 minutes (not 100)
(3) 47 days (not 24)

1. If the ball costs X amount, and the bat costs $1.00 more, the equation is x+1. X+ (X+1)= 1.1, then 2x=0.1, so X= 0.05.

2. The answer to this one is in the question. If it takes 5 machines 5 minutes to make 5 widgets, then one widget is created in 5 minutes. So, it would take 100 machines 5 minutes to make 100 widgets.

3. Every day moving forward, the patch doubles. So, every day backward would mean the patch halves in size. So, on day 47, the lake is half full, not day 24.

To be honest, my brain hurts. How did you do?

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