Question

A multiple choice test contains 8 questions with 3 answers to each question (of which one is only correct). A student answers each question by rolling a balanced dice and checking the first answer if he gets 1 or 2, the second answer if he gets 3 or 4, and third answer if he gets 5or 6. To get a distinction the students must secured at least 75 percentage correct answers. If there is no negative marking, what is the probability that the students get distinction?

Answer 1

Answer:

⁸C6 = 28

Step-by-step explanation:

Correct = 1/3

Incorrect = 2/3

75% × 8 = 75/100 × 8 = 6

P(6) = 8C6 × (1/3)⁶ × (2/3)² = 28×4/3⁸

P(7) = 8C7 × (1/3)⁷ × (2/3)¹ = 16/3⁸

P(8) = 8C8 × (1/3)⁸ × (2/3)⁰ = 1/3⁸

Țotal,

= P(6) + P(7) + P(8)

= (112 + 16 + 1)/3⁸ = 129/3⁸ = 129/6561 = 0.0196