Question
A multiple choice exam is made up of 10 questions; Each question has 5 options and only one of them is correct. If a person answers at random, what is the probability of answering only 3 good questions?
115
likes574 views
Answer to a math question A multiple choice exam is made up of 10 questions; Each question has 5 options and only one of them is correct. If a person answers at random, what is the probability of answering only 3 good questions?
Hermann
4.6126 Answers
Fórmula de probabilidad binomial P(X=k)=(n,k)*p^k * (1-p)^(nk)
n=10 (10 preguntas)
k=3 (3 respuestas correctas)
p=1/5 (probabilidad de responder correctamente a una pregunta, ya que hay 5 opciones y solo una es correcta
P(X=3)=(10,3)*(1/5)^3 * (4/5)^7
P(X=3)= (10!/3!7!)(1/5)^3 * (4/5)^7 = 0,201
Entonces, la probabilidad de responder correctamente sólo 3 preguntas es aproximadamente 0,201, o 20,1%.
Frequently asked questions (FAQs)
What is the surface area of a rectangular prism with dimensions 5 ft by 4 ft by 3 ft?
+
What is the measure, in radians, of an angle that completes 3 full revolutions?
+
What is the radius of a circle centered at (0,0) that satisfies the equation x^2 + y^2 = r^2?
+
New questions in Mathematics