Answer:
Each of the 3 digits can be from 0 to 9, so each of the digits can have 10 values.
10 * 10 * 10 = 1,000
However, if repetition is NOT allowed, then the first digit can be ANY digit (10 possibilities). The second digit can be ANY digit except what the first digit is (9 possibilities). The third digit can be ANY digit except what the first digit is or what the second digit is (8 possibilities).
Total area codes = 10 * 9 * 8 = 720
Answer is b
Step-by-step explanation:
