A Teacher makes up a 5 question multiple choice test. Each question has 5 answers listed "a-e". A new student takes the test on his first day of class. He has no prior knowledge of the material being tested.

a) What is the probability he makes a 100 by purely guessing?

b)What is the probability he only misses 2 questions?

c)What is the probability he misses more than 2 questions?

a) 5 nCr 5 * 1/5^5 * 4/5^0 = .00032

b) 5 nCr 3 * 1/5^3 * 4/5^2 = .0512

c) 5 nCr 2 * 1/5^2 * 4/5^3 + 5 nCr 1 * 1/5^1 * 4/5^3 + 5 nCr 0 * 1/5^0 * 4/5^5 = .94208

Did I do it right?
Maybe
a) .00032= 0.2 ^ 5

b) .008= 0.2 ^ 3

c) .64<
Last edited by Twisted Magnum at Feb 2, 2009,
Nope. The correct answer is - "Here's 5 bucks. Take the test for me."
Quote by SomeoneYouKnew
You should be careful what you say. Some asshole will probably sig it.

Quote by Axelfox
Yup, a girl went up to me in my fursuit one time.

Quote by Xiaoxi
I can fap to this. Keep going.
Quote by Jackal58
Nope. The correct answer is - "Here's 5 bucks. Take the test for me."

Well said.
'64 Fender Telecaster
'08 Epiphone Prophecy EM-2
'06 Epiphone Les Paul-100
'08 Squier Strat Mini
'03 Ibanez AEG10
'90 Yamaha FG730S
'31 Kay Archkraft
I shook my magic 8-ball, heres what it said:

"Outlook is bleak"
“Faith is the refuge of fools, the ignorant, and the deluded; not of thinking, rational men."

Do you have the answer key?
Why dont you fuck the teacher, cut her head open, and look for the answers there?

OF COURSE I WANT YOU TO GO GET THE ANSWER KEY!
I think c is wrong it should be 1 - (C(5,5)(1/5)^5 + C(5, 4)(1/5)^4*4/5) = 1- 0.00672 = 0.99328
my bad read it as 2 or more not more than 2 I think you're right