There are m boys and 12 girls in a class. What is the probability of selecting at random a girl from the class?

A.

\(\frac{m}{12}\)

B.

\(\frac{12}{m}\)

C.

\(\frac{12}{m+12}\)

D.

\(\frac{12}{m-12}\)

Correct answer is C

Prob. (a girl) \(=\frac{Number\hspace{1mm} of\hspace{1mm} girls}{Number \hspace{1mm} of \hspace{1mm} boys \hspace{1mm} and \hspace{1mm} girls\hspace{1mm} in \hspace{1mm} class}\\
= \frac{12}{m+12}\)