Probability

[AlexKom]

HEllo!
I have a trouble with probabilities and I need your help...

The probability of an event is 2/10, which means 1/5 = .2

What is the probability that it will be chosen for the first time by the 6th person in a line.
I think, that the solution is:
.2(.8^5) The probability that it will happen times the probability that it will not happen first 5 times. Is it right?

Thank you very much.

[JohnM]

Yes, that's correct.

[AlexKom]

And what if thee question is:
P(This event was chosen at least once in the first tree times)

I remember that it means that it is the same as the prob 1- that it was never chosen.
I think that the solution is:
1-(.2^3)= .992

Is it correct?

[JohnM]

= 1 - (.8^3)