Question

If p(a) = 2/3, p(b) = 4/5, and p(anb) = 3/5, what is P( AuB) ( the n is the arc shape direction, so is the u)

Answer 1

By the inclusion/exclusion principle,

`P(A\cup B) = P(A) + P(B) - P(A\cap B)`

`P(A\cup B) = \frac23 + \frac45 - \frac35`

`P(A\cup B) = (10)/(15) + (12)/(15) - \frac9{15}`

`P(A\cup B) = \boxed{(11)/(15)}`