Difference between revisions of "2018 AMC 8 Problems/Problem 16"
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Professor Chang has nine different language books lined up on a bookshelf: two Arabic, three German, and four Spanish. How many ways are there to arrange the nine books on the shelf keeping the Arabic books together and keeping the Spanish books together? | Professor Chang has nine different language books lined up on a bookshelf: two Arabic, three German, and four Spanish. How many ways are there to arrange the nine books on the shelf keeping the Arabic books together and keeping the Spanish books together? | ||
<math>\textbf{(A) }1440\qquad\textbf{(B) }2880\qquad\textbf{(C) }5760\qquad\textbf{(D) }182,440\qquad \textbf{(E) }362,880</math> | <math>\textbf{(A) }1440\qquad\textbf{(B) }2880\qquad\textbf{(C) }5760\qquad\textbf{(D) }182,440\qquad \textbf{(E) }362,880</math> | ||
+ | |||
+ | ==Solution== | ||
+ | Since the Arabic books and Spanish books have to be kept together, we can treat them both as just one book. That means we're trying to find the number of ways you can arrange one Arabic book, one Spanish book, and three German books, which is just <math>5</math> factorial. Now, we multiply this product by <math>2!</math> because there are <math>2!</math> ways to arrange the Arabic books within themselves, and <math>4!</math> ways to arrange the Spanish books within themselves. Multiplying all these together, we have <math>2! \cdot 4! \cdot 5!=\boxed{\textbf{(C) }5760}</math>. | ||
+ | |||
+ | ==Video Solution (CREATIVE ANALYSIS!!!)== | ||
+ | https://youtu.be/GznYT3zMh3o | ||
+ | |||
+ | ~Education, the Study of Everything | ||
+ | |||
+ | ==Video Solutions== | ||
+ | https://youtu.be/ci5Nwd1UnNE | ||
+ | |||
+ | https://youtu.be/FqyYAiyjCds | ||
+ | |||
+ | ~savannahsolver | ||
+ | |||
+ | https://www.youtube.com/watch?v=t1IARvN-JMM ~David | ||
+ | |||
+ | ==See Also== | ||
+ | {{AMC8 box|year=2018|num-b=15|num-a=17}} | ||
+ | |||
+ | {{MAA Notice}} |
Latest revision as of 15:17, 3 January 2024
Problem
Professor Chang has nine different language books lined up on a bookshelf: two Arabic, three German, and four Spanish. How many ways are there to arrange the nine books on the shelf keeping the Arabic books together and keeping the Spanish books together?
Solution
Since the Arabic books and Spanish books have to be kept together, we can treat them both as just one book. That means we're trying to find the number of ways you can arrange one Arabic book, one Spanish book, and three German books, which is just factorial. Now, we multiply this product by
because there are
ways to arrange the Arabic books within themselves, and
ways to arrange the Spanish books within themselves. Multiplying all these together, we have
.
Video Solution (CREATIVE ANALYSIS!!!)
~Education, the Study of Everything
Video Solutions
~savannahsolver
https://www.youtube.com/watch?v=t1IARvN-JMM ~David
See Also
2018 AMC 8 (Problems • Answer Key • Resources) | ||
Preceded by Problem 15 |
Followed by Problem 17 | |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25 | ||
All AJHSME/AMC 8 Problems and Solutions |
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions.