Difference between revisions of "1958 AHSME Problems/Problem 12"

(Created page with "==Problem== If <math> P \equal{} \frac{s}{(1 \plus{} k)^n}</math> then <math> n</math> equals: <math> \textbf{(A)}\ \frac{\log{\left(\frac{s}{P}\right)}}{\log{(1 \plus{} k)}}\q...")
 
m (See also)
Line 24: Line 24:
 
==See also==
 
==See also==
  
{{AHSME box|year=1958|num-b=11|num-a=13}}
+
{{AHSME 50p box|year=1958|num-b=11|num-a=13}}
 
{{MAA Notice}}
 
{{MAA Notice}}

Revision as of 05:07, 3 October 2014

Problem

If $P \equal{} \frac{s}{(1 \plus{} k)^n}$ (Error compiling LaTeX. Unknown error_msg) then $n$ equals:

$\textbf{(A)}\ \frac{\log{\left(\frac{s}{P}\right)}}{\log{(1 \plus{} k)}}\qquad \textbf{(B)}\ \log{\left(\frac{s}{P(1 \plus{} k)}\right)}\qquad \textbf{(C)}\ \log{\left(\frac{s \minus{} P}{1 \plus{} k}\right)}\qquad \\ \textbf{(D)}\ \log{\left(\frac{s}{P}\right)} \plus{} \log{(1 \plus{} k)}\qquad \textbf{(E)}\ \frac{\log{(s)}}{\log{(P(1 \plus{} k))}}$ (Error compiling LaTeX. Unknown error_msg)

Solution

\[P=\frac{s}{(1+k)^n}\]

\[(1+k)^n=\frac{s}{P}\]

Take the $\log$ of each side.

\[n \log(1+k) = \log\left(\frac{s}{P}\right)\]

\[n = \frac{\log\left(\frac{s}{P}\right)}{\log(1+k)} \to \boxed{\text{(A)}}\]


See also

1958 AHSC (ProblemsAnswer KeyResources)
Preceded by
Problem 11
Followed by
Problem 13
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 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
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