What is the probability of rolling a 3 on a number cube?

You flip a coin twice.  What is the complete sample space of possible combinations?

The cafeteria is serving three kinds of sandwiches:  tuna (T), chicken, (C), and peanut butter (P).  They are also serving a choice of two drinks:  milk (M) or water (W).  Which is the complete set of possibilities of combinations?

A bag has 10 marbles:  3 blue, 2 yellow, 4 red, and 1 purple.
What is the probability of picking out a purple marble?

A spinner has 8 sections: 2 purple, 2 yellow, 3 blue, and 1 red.
What is the probability of spinning and landing on a color that is not yellow?