1994 AJHSME Problems/Problem 25
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Contents
Problem
Find the sum of the digits in the answer to
where a string of nines is multiplied by a string of
fours.
Solution 1
Notice that:
and
and
So the sum of the digits of 9s times
4s is simply
(Try to find the proof that it works for all values of
~MATHWIZARD10).
Therefore the answer is
Solution 2
See Also
1994 AJHSME (Problems • Answer Key • Resources) | ||
Preceded by Problem 24 |
Followed by Last Problem | |
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All AJHSME/AMC 8 Problems and Solutions |
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