Difference between revisions of "2021 Fall AMC 12B Problems/Problem 6"
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| + | ==Video Solution by WhyMath== | ||
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| + | ~savannahsolver | ||
==See Also== | ==See Also== | ||
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{{AMC12 box|year=2021 Fall|ab=B|num-b=5|num-a=7}} | {{AMC12 box|year=2021 Fall|ab=B|num-b=5|num-a=7}} | ||
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Revision as of 06:31, 5 October 2022
- The following problem is from both the 2021 Fall AMC 10B #8 and 2021 Fall AMC 12B #6, so both problems redirect to this page.
Contents
Problem
The largest prime factor of 
is 
because 
. What is the sum of the digits of the greatest prime number that is a divisor of 
?
Solution (Difference of Squares)
We have
Since 
is composite, 
is the largest prime divisible by . The sum of 's digits is 
.
~Steven Chen (www.professorchenedu.com) ~NH14 ~kingofpineapplz ~Arcticturn ~MrThinker
Video Solution by Interstigation
https://youtu.be/p9_RH4s-kBA?t=1121
Video Solution
~Education, the Study of Everything
Video Solution by WhyMath
~savannahsolver
See Also
| 2021 Fall AMC 10B (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 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25 | ||
| All AMC 10 Problems and Solutions | ||
| 2021 Fall AMC 12B (Problems • Answer Key • Resources) | |
| Preceded by Problem 5 |
Followed by Problem 7 |
| 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 | |
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions. 
