MathDB
Choosing a Class Representative

Source:

March 2, 2009
probabilityratio

Problem Statement

One student in a class of boys and girls is chosen to represent the class. Each student is equally likely to be chosen and the probability that a boy is chosen is 23 \frac23 of the probability that a girl is chosen. The ratio of the number of boys to the total number of boys and girls is <spanclass=latexbold>(A)</span> 13<spanclass=latexbold>(B)</span> 25<spanclass=latexbold>(C)</span> 12<spanclass=latexbold>(D)</span> 35<spanclass=latexbold>(E)</span> 23 <span class='latex-bold'>(A)</span>\ \frac13 \qquad <span class='latex-bold'>(B)</span>\ \frac25 \qquad <span class='latex-bold'>(C)</span>\ \frac12 \qquad <span class='latex-bold'>(D)</span>\ \frac35 \qquad <span class='latex-bold'>(E)</span>\ \frac23