Lesson Logic problems - The solution to Problem 2

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The solution to Problem 2

Below (after the reminder) is the solution to the Problem 2 of the lesson Some logic problems (the topic Miscellaneous word problems
of the section Word problems in this site).

Problem 2 formulation (reminder)
A carpenter, a plumber, and an engineer, whose names are Alex, Bob, and Charlie, are flying from San Francisco to New York.
From their conversation in the plane it is revealed that
    a) Alex and the engineer are going to work at a construction site;
    b) the carpenter and Charlie live in Concord;
    c) Bob is younger than the plumber;
    d) Charlie is older than the engineer.
What are the names of the engineer and the carpenter?

Solution
Item a) of the problem statement means that Alex is not an engineer.
Item b) of the problem statement means that Charlie is not a carpenter.
Item c) of the problem statement implies that Bob is not a plumber.
Item d) of the problem statement means that Charlie is not an engineer.

Since Charlie is not a carpenter and is not an engineer, he is a plumber.

Since Alex is not an engineer, he is a carpenter or a plumber.
But we just found out that Charlie is a plumber.
Hence, Alex is a carpenter.

Now, for Bob there is only one opportunity: he is an engineer.

Answer
Alex is a carpenter.
Bob is an engineer.
Charlie is a plumber.

Back to the original lesson Some logic problems (the topic Miscellaneous word problems of the section Word problems in this site).

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