Question

time is running out when mike is taking a multiple choice test so he guesses on the last 5 questions. Each question has 4 possible choices. what is the probability that mike gets exactly 3 of these 5 questions correct?
1)100%
2) 60%
3)10.4%
4)8.8%

Answer 1

Why did he guess?

Answer 2

Why did mike take so long on the rest of his test?

Answer 3

use the binomial distribution formula


P(X = k) = (n C k)*(p)^(k)*(1-p)^(n-k)

In this case

n = 5
p = 0.25
k = 3


P(X = k) = (n C k)*(p)^(k)*(1-p)^(n-k)

P(X = 3) = (5 C 3)*(0.25)^(3)*(1-0.25)^(5-3)

P(X = 3) = (10)*(0.25)^(3)*(1-0.25)^(5-3)

I'll let you finish up

Answer 4

thank you!

Answer 5

np