3. A password is a sequence of letters (a-z) and digits (0-9). Find the number of passwordsof length 10 under the constraints in (a), (b) or (c) (three separate problems). Expressyour answer using factorials and integers, products and ratios of them, and/or sums ofsuch things.There are 3 letters and 7 digits, and at most one '9'.(b) There are 6 letters and 4 digits, and no digit occurs twice.(c) No letters are used BUT the first four digits are not all the same AND the last fourdigits are not all the same, AND the 4th, 5th, 6th and 7th digits are not all thesame.

Given that the number of letters (a-z) and the digits (0-9) is used to form a password of length…

3. A password is a sequence of letters (a-z) and digits (0-9). Find the number of passwords of length 10 under the constraints in (a), (b) or (c) (three separate problems). Express your answer using factorials and integers, products and ratios of them, and/or sums of such things. (a) There are 3 letters and 7 digits, and at most one '9'. (b) There are 6 letters and 4 digits, and no digit occurs twice. (c) No letters are used BUT the first four digits are not all the same AND the last four digits are not all the same, AND the 4th, 5th, 6th and 7th digits are not all the same.

3. A password is a sequence of letters (a-z) and digits (0-9). Find the number of passwords of length 10 under the constraints in (a), (b) or (c) (three separate problems). Express your answer using factorials and integers, products and ratios of them, and/or sums of such things. (a) There are 3 letters and 7 digits, and at most one '9'. (b) There are 6 letters and 4 digits, and no digit occurs twice. (c) No letters are used BUT the first four digits are not all the same AND the last four digits are not all the same, AND the 4th, 5th, 6th and 7th digits are not all the same.

Linear Algebra: A Modern Introduction

4th Edition

ISBN:9781285463247

Author:David Poole

Publisher:David Poole

Chapter2: Systems Of Linear Equations

Section2.4: Applications

Problem 24EQ: Suppose the coal and steel industries form a closed economy. Every $1 produced by the coal industry...

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Similar questions

Suppose the coal and steel industries form a closed economy. Every $1 produced by the coal industry requires $0.30 of coal and $0.70 of steel. Every $1 produced by steel requires $0.80 of coal and $0.20 of steel. Find the annual production (output) of coal and steel if the total annual production is $20 million.

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