1972 AHSME Problems/Problem 17

Revision as of 03:13, 7 November 2020 by Lopkiloinm (talk | contribs) (Created page with "== Problem 17 == A piece of string is cut in two at a point selected at random. The probability that the longer piece is at least x times as large as the shorter piece is <...")
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

Problem 17

A piece of string is cut in two at a point selected at random. The probability that the longer piece is at least x times as large as the shorter piece is

$\textbf{(A) }\frac{1}{2}\qquad \textbf{(B) }\frac{2}{x}\qquad \textbf{(C) }\frac{1}{x+1}\qquad \textbf{(D) }\frac{1}{x}\qquad \textbf{(E) }\frac{2}{x+1}$

Solution

The string could be represented by a line plot segment on the interval $(0,x+1)$. The interval $(0,1)$ is a solution as well as $(x,x+1)$. The probability is therefore $\boxed{\textbf{(E) }\frac{2}{x+1}}.$ ~lopkiloinm