Solution to Example 4

Test the validity of the following argument.

I will buy a new goat or a used Yugo.
If I buy both a new goat and a used Yugo, I will need a loan.
I bought a used Yugo and I don't need a loan.
Therefore, I didn't buy a new goat.

A. Valid
B. Invalid

We will reduce the argument to symbols, and use a truth table
to test its validity.

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