Directions Answer the questions. All problems are with replacement.1. How many 3-digit area codes can be made with the digits 0 through 9?2. If area codes were changed from 3-digit to 4-digit numbers, how many more area codes would be made available?3. How many 5-character PIN numbers can be made that contain 2 letters followed by 3 digits?4. In a certain city, all phone numbers begin with one of 5 different 3-digit exchanges. How many different telephone numbers are possible for this area?5. In the city in problem 4, how many new 3-digit exchanges would need to be added to allow for a total of 120,000 phone numbers?