WAEC - Mathematics (2004 - No. 8)
There are m boys and 12 girls in a class. What is the probability of selecting at random a girl from the class?
\(\frac{m}{12}\)
\(\frac{12}{m}\)
\(\frac{12}{m+12}\)
\(\frac{12}{m-12}\)
설명
Prob. (a girl) \(=\frac{Number\hspace{1mm} of\hspace{1mm} girls}{Number \hspace{1mm} of \hspace{1mm} boys \hspace{1mm} and \hspace{1mm} girls\hspace{1mm} in \hspace{1mm} class}\\
= \frac{12}{m+12}\)
= \frac{12}{m+12}\)