Difference between revisions of "2017 AMC 10B Problems/Problem 17"
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<math>\textbf{(A)}\ 1024\qquad\textbf{(B)}\ 1524\qquad\textbf{(C)}\ 1533\qquad\textbf{(D)}\ 1536\qquad\textbf{(E)}\ 2048</math> | <math>\textbf{(A)}\ 1024\qquad\textbf{(B)}\ 1524\qquad\textbf{(C)}\ 1533\qquad\textbf{(D)}\ 1536\qquad\textbf{(E)}\ 2048</math> | ||
==Solution== | ==Solution== | ||
| − | + | It adds in <math>9</math> at the end, but we know since it is MAA, it is probably a troll question, so we look at the answers. <math>(C)</math> looks likely, as it is just <math>(B)+9</math>, but we remember that MAA is trolly so it is probably <math>\boxed{\textbf{(B) }1524}</math>. | |
| + | |||
==See Also== | ==See Also== | ||
{{AMC10 box|year=2017|ab=B|num-b=16|num-a=18}} | {{AMC10 box|year=2017|ab=B|num-b=16|num-a=18}} | ||
{{MAA Notice}} | {{MAA Notice}} | ||
Revision as of 12:32, 16 February 2017
Problem
Call a positive integer 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
It adds in 
at the end, but we know since it is MAA, it is probably a troll question, so we look at the answers. 
looks likely, as it is just 
, but we remember that MAA is trolly so it is probably 
.
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 | ||
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions. 
