Question

If a coin is tossed 3 times, what is the probability of getting 3 tails?
A) 1/4
B) 1/9
C) 1/6
D) 1/8

Answer 1

@apoorvk

Answer 2

Hmm, once again - we need a sample space of all the possible outcomes. Can you make one this time? :]

Answer 3

p(tail) = 1/2
tossed 3 times in a sample space of \[2^{3}\]
it becomes:
\[p(tail _{3}) = (1/2)^{3} = 1/8\]

Answer 4

Sample space:
TH
HT
HH
TT
but three time because of three coins.

Answer 5

Umm, actually don't you think that's just for two coins? I can't see outcomes for the third coin in there.
Like 'TH' - tail for the first, head for the second, but the third?? ;)

Answer 6

Oh, haha okay.

Answer 7

Hmm, let me show you how:
So one easy way to count this is -
First I assume Tail for the first coin, and combine it with all the outcomes for '2 coins', then I fix Head, and do the same. Like this:

T - HT
T - TH
T - HH
T - TT
and
H-HT
H-TH
H-HH
H-TT

So, basically, I have the following outcomes:
THT
TTH
THH
TTT
HHT
HTH
HHH
TTT


Understandable?

Answer 8

yes. :3

Answer 9

So how many possible outcomes do I have, and how many among those are outcomes with 3 tails?

Answer 10

@darkzii ??