1. A quiz has a 5 multiple choice questions. Each questions has 4 answer choices of which one is the correct answer and the other 3 are incorrect. Suppose you guess the answer.

a. How many ways are ther to answer the 5 questions?

b. What is the probabilty of getting all 5 questions right?

c. What is the probability of getting exactly 4 questions right? and 1 wrong?

d. What is the probability of doing well getting atleast 4 right answers?

Expert Answers

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Since the problem provides the information that each of the 5 questions has 4 answer choices, you may evaluate the probability to have 5 questions right, such that:

`P = (1/4)^5 => P = 1/1024 => P = 0.0009765625`

The probability to get exactly 4 questions right and 1 wrong may be evaluated such that:

`P = 1/4 = 0.25`

`P = 3/4 = 0.75 `

`P = C_5^1*(1/4)^4*(3/4) => P = 5*0.25^4*0.75 = 0.0146 ` (exactly 4 questions correct)

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