Difference between revisions of "2001 AMC 12 Problems/Problem 2"
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+ | {{duplicate|[[2001 AMC 12 Problems|2001 AMC 12 #2]] and [[2002 AMC 10A Problems|2002 AMC 10A #6]]}} | ||
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== Problem == | == Problem == | ||
Let <math>P(n)</math> and <math>S(n)</math> denote the product and the sum, respectively, of the digits | Let <math>P(n)</math> and <math>S(n)</math> denote the product and the sum, respectively, of the digits |
Revision as of 15:37, 16 March 2011
- The following problem is from both the 2001 AMC 12 #2 and 2002 AMC 10A #6, so both problems redirect to this page.
Problem
Let and denote the product and the sum, respectively, of the digits of the integer . For example, and . Suppose is a two-digit number such that . What is the units digit of ?
Solution
Denote and as the tens and units digit of , respectively. Then . It follows that , which implies that . Since , . So the answer is .
See Also
2001 AMC 12 (Problems • Answer Key • Resources) | |
Preceded by Problem 1 |
Followed by Problem 3 |
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 |
2001 AMC 10 (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 10 Problems and Solutions |