Difference between revisions of "2016 AMC 10A Problems/Problem 1"
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| + | ==Problem== | ||
| + | |||
What is the value of <math>\dfrac{11!-10!}{9!}</math>? | What is the value of <math>\dfrac{11!-10!}{9!}</math>? | ||
<math>\textbf{(A)}\ 99\qquad\textbf{(B)}\ 100\qquad\textbf{(C)}\ 110\qquad\textbf{(D)}\ 121\qquad\textbf{(E)}\ 132</math> | <math>\textbf{(A)}\ 99\qquad\textbf{(B)}\ 100\qquad\textbf{(C)}\ 110\qquad\textbf{(D)}\ 121\qquad\textbf{(E)}\ 132</math> | ||
| − | + | ==Solution== | |
| − | < | + | <cmath>\frac{11!-10!}{9!} = \frac{9!(10 \cdot 11 -10)}{9!} = 10 \cdot 11 - 10 =\boxed{\textbf{(B)} 100}</cmath> |
Revision as of 17:58, 3 February 2016
Problem
What is the value of 
?
Solution
![\[\frac{11!-10!}{9!} = \frac{9!(10 \cdot 11 -10)}{9!} = 10 \cdot 11 - 10 =\boxed{\textbf{(B)} 100}\]](http://latex.artofproblemsolving.com/b/d/1/bd1a578c392c549881f296f48493cd9d504cf1fa.png)
