Difference between revisions of "1983 AIME Problems/Problem 8"
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First notice that | First notice that | ||
| − | <math></math> | + | <math></math>200\choose100=\frac{200!}{100!100!}= |
== See Also == | == See Also == | ||
Revision as of 10:34, 14 August 2019
Problem
What is the largest 
-digit prime factor of the integer 
?
Solution
Expanding the binomial coefficient, we get 
. Let the required prime be 
; then 
. If 
, then the factor of appears twice in the denominator. Thus, we need to appear as a factor at least three times in the numerator, so 
. The largest such prime is 
, which is our answer.
Solution 2: Clarification of Solution 1
First notice that $$ (Error compiling LaTeX. Unknown error_msg)200\choose100=\frac{200!}{100!100!}=
See Also
| 1983 AIME (Problems • Answer Key • Resources) | ||
| Preceded by Problem 7 |
Followed by Problem 9 | |
| 1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 | ||
| All AIME Problems and Solutions | ||
