If Zaleha is in a good mood, then she will study. Zaleha will play computer games whenever she did not study, then. Zaleha plays computer games only if she will not do anything else. Zaleha is in a good mood, or she is doing something else. Therefore, Zaleha will study.

1. Write each primary statement in Figure 1.0 by using the variables r, s, t and u.
2. Write all the hypothesis or premises and
3. Use the rules of inference and the rules of logic to derive the conclusion.