(a) To log on to a certain computer account, the user must type in a 4 -letter password. In such a password, no letter may be repeated, and only the lower case of a letter may be used. How many such 4 -letter passwords are possible? (There are 26 letters in the alphabet.) (b) A certain committee consists of 15 people. From the committee, a president, a vice-president, a secretary, and a treasurer are to be chosen. In how many ways can these 4 offices be filled? Assume that a committee member can hold at most one of these offices.
(a) To log on to a certain computer account, the user must type in a 4 -letter password. In such a password, no letter may be repeated, and only the lower case of a letter may be used. How many such 4 -letter passwords are possible? (There are 26 letters in the alphabet.) (b) A certain committee consists of 15 people. From the committee, a president, a vice-president, a secretary, and a treasurer are to be chosen. In how many ways can these 4 offices be filled? Assume that a committee member can hold at most one of these offices.
A First Course in Probability (10th Edition)
10th Edition
ISBN:9780134753119
Author:Sheldon Ross
Publisher:Sheldon Ross
Chapter1: Combinatorial Analysis
Section: Chapter Questions
Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...
Related questions
Question
(a) To log on to a certain computer account, the user must type in a
4
4
26
|
|
(b) A certain committee consists of
15
4
offices be filled? Assume that a committee member can hold at most one of these offices.
|
|
Expert Solution
Step 1: Define the initial Variables and find 'a'
a)
The number of letters password that user must type = 4
As given,
No letters may be repeated.
Only the lower case letters may be used.
Total number of letters = 26
The number of 4-letter passwords are possible are,
= 26*25*24*23
= 358800
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