Find the number using the following Venn diagram. n(A U BC) U A B 12 11 17 16 A computer password is to consist of four alphanumeric characters with no repeats. (An alphanumeric character is a letter from A to Z or a digit from 0 to 9.) How many such passwords are there? X passwords How many are there if the letter O and the digit 0 are excluded to avoid confusion? X passwords A telephone number consists of seven digits, and the first digit cannot be a zero or a one. How many telephone numbers have no repeated digits? telephone numbers