Difference between revisions of "2020 AMC 8 Problems/Problem 12"
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<cmath>10!*12=12*N!.</cmath> | <cmath>10!*12=12*N!.</cmath> | ||
− | We can cancel the <math> | + | We can cancel the <math>12</math>'s, since we are multiplying them on both sides of the equation. |
We have | We have | ||
<cmath>10!=N!.</cmath> | <cmath>10!=N!.</cmath> | ||
− | From here, it is obvious that <math>N=10(A).</math> | + | From here, it is obvious that <math>N=\boxed{10\textbf{(A)}}.</math> |
-iiRishabii | -iiRishabii |
Revision as of 23:59, 17 November 2020
For positive integers , the notation denotes the product of the integers from to . What value of satisfies the following equation?
Solution 1
Notice that = and we can combine the numbers to create a larger factorial. To turn into we need to multiply by which equals to
Therefore, we have
We can cancel the 's, since we are multiplying them on both sides of the equation.
We have
From here, it is obvious that
-iiRishabii