Difference between revisions of "2017 AMC 10B Problems/Problem 17"
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==Problem== | ==Problem== | ||
| − | + | Call a positive integer \textit{monotonous} if it is a one-digit number or its digits, when read from left to right, form either a strictly increasing or a strictly decreasing sequence. For example, <math>3</math>, <math>23578</math>, and <math>987620</math> are monotonous, but <math>88</math>, <math>7434</math>, and <math>23557</math> are not. How many monotonous positive integers are there? | |
| + | <math>\textbf{(A)}\ 1024\qquad\textbf{(B)}\ 1524\qquad\textbf{(C)}\ 1533\qquad\textbf{(D)}\ 1536\qquad\textbf{(E)}\ 2048</math> | ||
==Solution== | ==Solution== | ||
Placeholder | Placeholder | ||
Revision as of 12:27, 16 February 2017
Problem
Call a positive integer \textit{monotonous} if it is a one-digit number or its digits, when read from left to right, form either a strictly increasing or a strictly decreasing sequence. For example, 
, 
, and 
are monotonous, but 
, 
, and 
are not. How many monotonous positive integers are there?
Solution
Placeholder
See Also
| 2017 AMC 10B (Problems • Answer Key • Resources) | ||
| Preceded by Problem 16 |
Followed by Problem 18 | |
| 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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