what is the propability of rolling a sum of 7 or 11 with 2 6 sided number cubes?

Thanks phil. That really helped me.

P ( 7 or 11)  = P(7) + P(11) - P(7 and 11)

P( 7 or 11) = 6/36  + 2/36  -  0/36 

P(7 or 11)  = 8/36   =  2 / 9  

[Note P(7 and 11)  = 0/36   because we can't roll a 7 and an 11 at the same time !! ]

No prob !!!!