The Homa Files

The following is a three question Cognitive Reflection Test (CRT), a sort of mini IQ test. Give it a try.

1. A bat and a ball together cost 110 cents. The bat costs 100 cents more than the ball. How much does the ball 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’s 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 the lake

Actually, the CRT doesn’t purport to measure intelligence in any meaningful sense.

Rather, it’s a test of willingness to think things through and check your answers.

All three items are gotcha questions to which the first incident occurs to just about everyone is wrong.

Scroll down for answers …

If you got two or three of the questions right you are “reflective”– that’s good.

If you got none or one right, you’re “impulsive”. You can draw your own conclusion on that one.  In fact since you’re impulsive, you probably have already have.

Source: Priceless, William Poundstone, Hill and Wang Books, 2010

* * * *  *

Answers: 5 cents, 5 minutes, 47 days

This entry was posted on September 7, 2010 at 6:30 am and is filed under Problem solving. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.