contestada

A multiple choice test has 30 questions. each question has five possible answers, of which one is correct. if a student guesses on every question, find the probability of getting exactly 12 correct.

Respuesta :

Total number of questions = 30
Probability of getting an answer right = 1/5 
Probability of getting an answer wrong = 4/5 
Number of questions to be correct = 12
Number of questions to be wrong = 30 - 12 = 18

[tex] \left(\begin{array}{c}30\\12\end{array}\right) \left(\begin{ \dfrac{1}{5} }\right)^{12}\left(\begin{ \dfrac{4}{5} }\right)^{18} = 0.06[/tex]

Otras preguntas