Question: Some metals are conductive. All conductive materials are useful. Which of the following conclusions can be drawn?

Options:

1. All useful materials are metals.
2. Some useful materials are not metals.
3. Some metals are not useful.
4. All conductive materials are metals.

Correct Answer: Some useful materials are not metals.

Solution:

Since some metals are conductive and all conductive materials are useful, it can be concluded that some useful materials are not metals.