Statistics question

The way I see it is you already have a 6. To get two sixes you must get a 6 on the second roll. This is P(get a six) on one die throw. However this does not give 1/11, so I'm not sure your answer is correct. Maybe somebody could confirm this.

nope its a normal dice.. theres another question that goes by A red and a blue die are rolled. Given that there is at least one six, what is the probability that the red die is showing six? -- the answer is 6/11

What can you get with two dice? How many of these situations have at least one 6, and how many have two 6s?



Don't think so.

hang on I still dont understand

6*6 grid of possible results. How many squares have at least one 6? How many squares have 2 sixes?

How would you have come to that answer using the formulas?

How would you have come to that answer using the formulas?

Depends what formulas you're talking about. You want P(two sixes|at least one six)=P(2 sixes)/P(at least one six), yes? Clearly the numerator is 1/36 - can you see how to calculate the denominator?

how do you calculate the denominator?

See metaltron's post above mine.

I have, but i still dont get it. I haven't drawn out the 6*6 grid cause in an exam i just wouldn't' have time. how else would i work that there is at least one 6?

Metaltron's post (literally right above the one you quoted) doesn't even mention a 6*6 grid. Denominator=1-P(0sixes)=1-P(1st dice isn't a 6)*P(2nd dice isn't a 6)

Edit - also, you'd never actually draw a 6*6 grid, you just need to think about it.

Oh i see. Okay its getting late and my brain seems dead but is 1 - P(0 sixes) the only way to work out that there is at least 1 six?