Brainteasers – Issue 20, 2011


1. Shopping Cart Jumble

An engineer went to: to purchase some high-value automation parts. She purchased various quantities of three parts: proximity sensors at $50 each, Stable motor mounting bases at $10 each, and Nitra pneumatic fittings at $0.50 each. She purchased a total of 100 parts, and spent exactly $1000 dollars (qualifying her order for free 2-day shipping). Can you calculate how many of each part she purchased?

2. IO, IO, It’s off to Work We Go

A PLC system contains 36 I/O modules and a total of 100 I/O points. All the input modules are 4 point, and all the output modules are 2 point – except for one 6 point input and one 4 point output. Can you discern the number of input vs. output modules in the system?

3. Quarter Time

The hopper of a packaging machine is filled with widgets on Monday morning. Each day the machine packages a single widget as a test sample, and then proceeds to package one quarter of the remaining widgets from the hopper. Recordkeeping is minimal, but it is noted that the number of widgets packaged on Monday and Wednesday is exactly 100 more than the number packaged on Tuesday and Thursday. At the end of the day, Thursday, the production manager asks how many widgets remain in the hopper. Can you tell him?

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Don’t Judge A Driver By The Car!

As told by a tour guide at the Edison & Ford Winter Estates Museum in Ft. Myers, FL. The tour guide prefaced the story by admitting that they couldn’t verify it, so read it at your own risk!

It seems that Henry Ford was driving on a remote road one day and happened upon a stranded motorist with a broken-down car by the side of the road. As Mr. Ford was a very competent engineer and mechanic, he stopped to help. Without being recognized (or introducing himself) he rolled up his sleeves and spent more than a few minutes diagnosing and ultimately fixing the car’s engine. Once he was finished, the impressed motorist thanked him, and tried to offer him some money for his time and effort. Mr. Ford had to decline the offered money several times saying, “No thank you, I have all the money in the world – it’s simply not necessary.” The motorist apparently got somewhat annoyed by that repeated phrase, and finally retorted “If you have all the money in the world, then why are you driving a Ford?”

If you are ever in the Ft. Myers, Florida area, be sure to visit the Edison & Ford Winter Estates. It’s a fascinating museum for anyone interested in technology or history. Learn more at:

One thought on “Brainteasers – Issue 20, 2011

  1. […] In each issue of the Automation Notebook we feature a section of brainteasers. These are the brainteaser answers from Issue 20, 2011 of the Automation Notebook. The brainteaser questions are repeated in black. The answers to the brainteaser questions are highlighted in red with explanations. You can view the brainteasers from Issue 20, 2011 without the answers here: […]