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SUMMARY

This discussion focuses on solving combinatorial problems involving arrangements and combinations. The first problem involves arranging four French books, two English books, and three German books on a shelf while keeping books of the same language together, which can be calculated using the fundamental counting principle. The second problem addresses the arrangements of the word "equation" with vowels treated as a single unit, leading to a specific calculation of permutations. The third problem examines a five-digit combination lock, detailing the number of possible combinations with and without digit repetition.

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Asawira Emaan
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Asalamoalikum,

Kindly can someone solve these with explanation?

1. In how many ways can four French books, two English books and three German books be arranged on a shelf so that all books in same language are together.

2. How many different arrangements can be formed of the word "equation" if all the vowels are to be kept together?

3. A combination lock has five wheels, each labeled with the ten digits from 0 to 9. How many five number opening combinations are possible,
(i) assuming no digit is repeated.
(ii)assuming digits can be repeated.

Thank you.
 
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Asawira Emaan said:
Asalamoalikum,

Kindly can someone solve these with explanation?
You won't learn anything by people doing your homework for you! Here are some hints:

1. In how many ways can four French books, two English books and three German books be arranged on a shelf so that all books in same language are together.
First, treat the books of each language, which must be kept together, as one object. In how many ways can you arrange 3 objects? Now, in how many ways can you arrange just the 4 French books? The two English books? The three German books? By the "fundamental counting principle", multiply those.

2. How many different arrangements can be formed of the word "equation" if all the vowels are to be kept together?
Treat the vowels, e, u a, i, and o, that are to be kept together, as a single letter. there are also 3 consonants so, treating the vowels as a single letter, there are 4 objects. In how many ways can you arrange 4 objects. In how many ways can you arrange the 5 vowels?

3. A combination lock has five wheels, each labeled with the ten digits from 0 to 9. How many five number opening combinations are possible,
(i) assuming no digit is repeated.
There are 10 choices for the first digit, then 9 for the second, etc.

(ii)assuming digits can be repeated.
Then there are 10 choices for every digit.

Thank you.
 
Country Boy said:
You won't learn anything by people doing your homework for you! Here are some hints:First, treat the books of each language, which must be kept together, as one object. In how many ways can you arrange 3 objects? Now, in how many ways can you arrange just the 4 French books? The two English books? The three German books? By the "fundamental counting principle", multiply those. Treat the vowels, e, u a, i, and o, that are to be kept together, as a single letter. there are also 3 consonants so, treating the vowels as a single letter, there are 4 objects. In how many ways can you arrange 4 objects. In how many ways can you arrange the 5 vowels?There are 10 choices for the first digit, then 9 for the second, etc.Then there are 10 choices for every digit.
Thanks by the time I got this answer I had already done the homework.
 
Good! That's the way it should be!
 

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