Difference between revisions of "2024 AMC 10B Problems/Problem 2"

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{{duplicate|[[2024 AMC 10B Problems/Problem 2|2024 AMC 10B #2]] and [[2024 AMC 12B Problems/Problem 2|2024 AMC 12B #2]]}}
  
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==Problem==
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What is <math>10! - 7! \cdot 6!</math>
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<math>\textbf{(A) } -120 \qquad\textbf{(B) } 0 \qquad\textbf{(C) } 120 \qquad\textbf{(D) } 600 \qquad\textbf{(E) } 720</math>
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==Solution 1==
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<math>10! = 10 \cdot 9 \cdot 8 \cdot 7! = 720 \cdot 7!</math>
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<math>6! \cdot 7! = 720 \cdot 7!</math>
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Therefore, the equation is equal to <math>720 \cdot 7! - 720 \cdot 7! = \boxed{\textbf{(B) }0}</math>
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~ARay10
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==See also==
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{{AMC10 box|year=2024|ab=B|num-b=1|num-a=3}}
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{{AMC12 box|year=2024|ab=B|num-b=1|num-a=3}}
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{{MAA Notice}}

Revision as of 00:20, 14 November 2024

The following problem is from both the 2024 AMC 10B #2 and 2024 AMC 12B #2, so both problems redirect to this page.

Problem

What is $10! - 7! \cdot 6!$

$\textbf{(A) } -120 \qquad\textbf{(B) } 0 \qquad\textbf{(C) } 120 \qquad\textbf{(D) } 600 \qquad\textbf{(E) } 720$

Solution 1

$10! = 10 \cdot 9 \cdot 8 \cdot 7! = 720 \cdot 7!$

$6! \cdot 7! = 720 \cdot 7!$

Therefore, the equation is equal to $720 \cdot 7! - 720 \cdot 7! = \boxed{\textbf{(B) }0}$

~ARay10

See also

2024 AMC 10B (ProblemsAnswer KeyResources)
Preceded by
Problem 1
Followed by
Problem 3
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 AMC 10 Problems and Solutions
2024 AMC 12B (ProblemsAnswer KeyResources)
Preceded by
Problem 1
Followed by
Problem 3
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 AMC 12 Problems and Solutions

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