# Math Help - Probability problem

1. ## Probability problem

Hello, I need some help with one math problem:
"There are TWO events, one of these events has probability 0,84. (nothing is said about other event ) What probability is to have 4 of 6 such events occured."
As I imagine these events should happen in pairs [0,84, ???], [0,84, ???] and [0,84, ???].
6 events, 3 probabilities unknown.
any ideas?

2. Originally Posted by edvintas
Hello, I need some help with one math problem:
"There are TWO events, one of these events has probability 0,84. (nothing is said about other event ) What probability is to have 4 of 6 such events occured."
As I imagine these events should happen in pairs [0,84, ???], [0,84, ???] and [0,84, ???].
6 events, 3 probabilities unknown.
any ideas?
Please post the whole question exactly as it's written. What you've posted makes no sense.

3. ## hi

Hi

As Mr.Fantastic said, you really should try to make your posts as clear as possible. Now I am just guessing what you mean here..

You say you have TWO events, $A_{1} \mbox{ and } A_{2}$
If $P(A_{1}) = 0.84 \, \Rightarrow \, P(A_{2}) = 1-P(A_{1}) = 0.16$

If you mean chances of $A_{1}$ happening 6 times in a row, then $(P(A_{1}))^{6} \approx 0.35$

This is also assuming that the probabilities remain constant etc.

If you wonder what are the chances of for example $A_{1}$ occuring 4 times and $A_{2}$ occuring 2 times, I´d recommend the Binomial formula.( Check wikipedia or search forum for more info on binomil distribution).

Hope this helps a little..