Solution to Example 1

Use a truth table to test the validity of the following argument.

If you invest in the Gomermatic Corporation, then you get rich.
You didn't invest in the Gomermatic Corporation.
Therefore, you didn't get rich.

A. Valid
B. Invalid

Step 1

Symbolize the argument.
Let p be the statement "You invest in the Gomermatic Corporation."
Let q be the statement "You get rich."

Then the argument has this symbolic form:

Step 2

Make a truth table having a column for each premise and for the conclusion.

Step 3

Interpret the truth table.
Notice that in the third row, the conclusion is FALSE while both premises are TRUE.
This tells us that the argument is INVALID.

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