Difference between revisions of "1968 AHSME Problems/Problem 16"

m (Solution)
(Solution)
 
(One intermediate revision by one other user not shown)
Line 10: Line 10:
  
 
== Solution ==
 
== Solution ==
<math>\fbox{E}</math>
+
 
 +
Because <math>\frac{1}{x}<2</math>, <math>x>\frac{1}{2}</math> when <math>x</math> is positive. Because <math>\frac{1}{x}>-3</math>, <math>x<\frac{-1}{3}</math> when <math>x</math> is negative. <math>x</math> can never be <math>0</math>, so these two inequalities cover all cases for the value of <math>x</math>. Thus, our answer is <math>\fbox{E}</math>.
  
 
== See also ==
 
== See also ==
{{AHSME box|year=1968|num-b=15|num-a=17}}   
+
{{AHSME 35p box|year=1968|num-b=15|num-a=17}}   
  
 
[[Category: Introductory Algebra Problems]]
 
[[Category: Introductory Algebra Problems]]
 
{{MAA Notice}}
 
{{MAA Notice}}

Latest revision as of 19:46, 17 July 2024

Problem

If $x$ is such that $\frac{1}{x}<2$ and $\frac{1}{x}>-3$, then:

$\text{(A) } -\frac{1}{3}<x<\frac{1}{2}\quad \text{(B) } -\frac{1}{2}<x<3\quad \text{(C) } x>\frac{1}{2}\quad\\ \text{(D) } x>\frac{1}{2} \text{ or} -\frac{1}{3}<x<0\quad \text{(E) } x>\frac{1}{2} \text{ or } x<-\frac{1}{3}$

Solution

Because $\frac{1}{x}<2$, $x>\frac{1}{2}$ when $x$ is positive. Because $\frac{1}{x}>-3$, $x<\frac{-1}{3}$ when $x$ is negative. $x$ can never be $0$, so these two inequalities cover all cases for the value of $x$. Thus, our answer is $\fbox{E}$.

See also

1968 AHSC (ProblemsAnswer KeyResources)
Preceded by
Problem 15
Followed by
Problem 17
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 31 32 33 34 35
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