2020 AMC 8 Problems/Problem 12
For a positive integer , the factorial notation
represents 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
Solution 2
\implies\boxed{\textbf{(A) }10}$.
~jmansuri
See also
2020 AMC 8 (Problems • Answer Key • Resources) | ||
Preceded by Problem 11 |
Followed by Problem 13 | |
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