# Thread: Probability homework help

1. ## Probability homework help

I'm usually good at maths but statistics and probability are my worst qualities....

Here's the question:

Two cubical fair dice are thrown, one red and one blue. The scores on their faces are added together. What is the probability that...

a) the total score will be 10 or more given that the red dice shows a 6
b) the total score will be 10 more more given that at least one dice shows a 6

Thanks guys

2. Originally Posted by anthmoo
I'm usually good at maths but statistics and probability are my worst qualities....

Here's the question:

Two cubical fair dice are thrown, one red and one blue. The scores on their faces are added together. What is the probability that...

a) the total score will be 10 or more given that the red dice shows a 6
b) the total score will be 10 more more given that at least one dice shows a 6

Thanks guys
a) Given the red shows a 6, there are six points (r,b) in the sample space all
equally likley (6,1) (6,2) ... (6,6)

Of these six (6,4), (6,5) and (6,6) have a total greater than or equal to 10,
so the required prob

p = (#favourable cases)/(total ' of equally likley cases) =3/6=1/2

b) The sample space is: (6,1), (6,2), ..., (6,6), (1,6), (2,6), ..., (5,6).
The outcomes that satisfy the condition are:

(6,4), (6,5), (6,6), (4,6), (5,6)

a total of 5, out of a grand total of 11 (don't count (6,6) twice!), so the required
prob is

p = 5/11

RonL