2021 Fall AMC 10B Problems/Problem 8
Contents
Problem 8
The largest prime factor of is
, because
. What is the sum of the digits of the largest prime factor of
?
Solution 1
We have
Since
is prime, our answer is
.
~kingofpineapplz
Solution 2
Since is
, we can consider it as
.
is
less than
, so it can be considered as
less than a square. Therefore, it can be expressed as
. Since
is
is
.
is
, and since
is larger, our answer is
.
~Arcticturn
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 |
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