Difference between revisions of "1990 AHSME Problems/Problem 17"

(Created page with "== Problem == How many of the numbers, <math>100,101,\cdots,999</math> have three different digits in increasing order or in decreasing order? <math>\text{(A) } 120\quad \text{(...")
 
(Solution)
Line 9: Line 9:
  
 
== Solution ==
 
== Solution ==
<math>\fbox{B}</math>
+
<math>\fbox{C}</math>
  
 
== See also ==
 
== See also ==

Revision as of 13:18, 3 August 2015

Problem

How many of the numbers, $100,101,\cdots,999$ have three different digits in increasing order or in decreasing order?

$\text{(A) } 120\quad \text{(B) } 168\quad \text{(C) } 204\quad \text{(D) } 216\quad \text{(E) } 240$

Solution

$\fbox{C}$

See also

1990 AHSME (ProblemsAnswer KeyResources)
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 26 27 28 29 30
All AHSME Problems and Solutions

The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions. AMC logo.png