2022 AMC 12B Problems/Problem 3
Problem
How many of the first ten numbers of the sequence ,
,
, ... are prime numbers?
Solution 1
Let denote the digit
written
times and let
denote the concatenation of
,
, ...,
.
Observe that
Clearly, both terms are larger than
since
, hence all the numbers of the sequence are
, and we're done!
~Bxiao31415
See Also
2022 AMC 12B (Problems • Answer Key • Resources) | |
Preceded by Problem 2 |
Followed by Problem 4 |
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 |
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