Automation NotebookIssue 12 – 2008Learning ResourcesNotebook IssueThe Break Room

Brainteaser Answers – Issue 12, 2008

In each issue of the Automation Notebook we feature a section of brainteasers. These are the brainteaser answers from Issue 12, 2008 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 12, 2008 without the answers here:

1. Tank You Very Much

In a factory far, far away – a tank is filled 1/3 full with an unidentified liquid, and another tank of the same size is filled ¼ full with the same non-hazardous fluid. Both tanks are then topped off with water and mixed thoroughly. The resulting mixtures are pumped into a larger vessel and mixed together, before being returned to the original tanks. What is the resulting ratio of the unknown liquid to the water in each of the tanks?

Answer: The ratio is 7 parts unidentified liquid to 17 parts water.

Answer explained: With fractions of 1/3 and 1/4 the least common denominator is 12. So we can say that the tanks are filled with 4/12ths and 3/12ths “fluid” respectively. That’s 4 parts “fluid” to 8 parts water in the first tank, and 3 parts “fluid” to 9 parts water in the second. Mixed together this yields 7 parts “fluid” to 17 parts water in the “larger vessel”. Assuming a good mixing, and that that the fluids stay mixed (i.e. nothing precipitates to the bottom of the tank) it really doesn’t mater how you divide it up after that it, the ratio will remain the same 7:17.

2. Slither Link

(also known as Fences and Puzzle-Loop) is a type of logic puzzle with simple rules and challenging solutions.

The rules are simple. You draw lines between the dots to form a single route (or ‘loop’) without crossings or branches. The numbers in each square indicate how many lines will be drawn about that square. A square with no number can have any number of lines bounding it. You can use logic to solve these puzzles, guessing should not be required.
Here is a simple Slither Link with the solution shown on the right:



Loop Puzzle 1.)


Answer: Loop Puzzle 1.)


Loop Puzzle 2.)


Answer: Loop Puzzle 2.)


Puzzles courtesy

For more Slither Link puzzles (including much harder ones) and/or more tips and hints please visit