MathDB
Minimum Value of a Product

Source:

January 18, 2009
inequalitiescalculussymmetryfunctionalgebradomain

Problem Statement

Let x x,y y, and z z be three positive real numbers whose sum is 1 1. If no one of these numbers is more than twice any other, then the minimum possible value of the product xyz xyz is <spanclass=latexbold>(A)</span> 132<spanclass=latexbold>(B)</span> 136<spanclass=latexbold>(C)</span> 4125<spanclass=latexbold>(D)</span> 1127<spanclass=latexbold>(E)</span> none of these <span class='latex-bold'>(A)</span>\ \frac{1}{32}\qquad <span class='latex-bold'>(B)</span>\ \frac{1}{36}\qquad <span class='latex-bold'>(C)</span>\ \frac{4}{125}\qquad <span class='latex-bold'>(D)</span>\ \frac{1}{127}\qquad <span class='latex-bold'>(E)</span>\ \text{none of these}