1. Each of the 10 questions on a multiple-choice exam has four possible answers. How many different ways are there for a student to answer the questions? Assume that every question must be answered.
2. Rework Exercise 41 under the assumption that not every question must be answered.
3. 43. How many ZIP codes are possible?
4. ZIP codes for Delaware, New York, and Pennsylvania begin with the digit 1. How many such ZIP codes are possible?