1. Prove that every odd number n ends in 1 in its binary representation.
2. Scary Clown offers a Sad Meal containing a sandwich, a salad, a dessert, and a drink. (They are not mixed together in the box.) There are 11 types of sandwiches, 3 types of salads, and 5 different kinds of desserts. A person with low standards for food could eat a different Sad Meal every day for three years. So how many drinks are possible choices for a Sad Meal?