MTH 150 Lecture Notes - Lecture 22: Microcomputer, Product Rule, The Chairs
Document Summary
Product rule: a procedure can be broken down into a sequence of two tasks. 2600 e. g. 32 microcomputers in a computer center. 23 + 15 + 19 = 57 e. g. password of 6-8 characters long. Each password must contain at least one digit. Total passwords just letters = 26^6 = 308,915,776. Actual number of passwords = 36^6 - 26^6 = 1,867,866,560. Total passwords just letters = 26^7 = 8e9. Actual number of passwords = 36^7 - 26^7 = 7e10. Total passwords just letters = 26^8 = 2e11. Actual number of passwords = 36^8 - 26^8 = 2e12. How many bit string of length 8 either start with 1 or end with 00. # bit string start with 1 or end with 00 = # bit string start with 1 + bit string end 00 - # bit string start with. 1 and end with 00. (subtraction is done to prevent counting twice)
