Originally Posted by
ovi8 A pair of dice is rolled. What are the odds in favor of each of the following events occuring?
a) a sum of 7 turning up
b) a sum of 11 turning up
c) a sum of 7 or a sum of 11 turning up
here is what i have so far..
a) n(S) = 6x6=36
E(rolling a 7) = {(1,6),(2,5),(4,3),(6,1),(5,2),(3,4)}
n(E)= 6
P(E)= 6/36 simplified 1/6
so getting the odds would be..
1/6 / 5/6 = 1/5
therefore the odds are 1 to 5
b) n(S) = 6x6=36
E(rolling a 11) = {(6,5),(5,6)}
n(E)= 2
P(E)= 2/36 simplified 1/18
so getting the odds would be..
1/18 / 17/18 = 1/17
therefore the odds are 1 to 17
c) a sum of 7 or a sum of 11 turning up
probability of rolling a 7 = 1/6
probability of rolling a 11 = 1/18
1/6x1/18 = 1/108
P(E)/P(E') = 1/108/107/108 = 1/107
therefore the odds are 1 to 107
any help would be greatly appreciated.