Question

Suppose that a and b are two independent events with p(a)=0.2 and p(b)=0.4. p(a or
b.is

Answer 1

Recall that


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

Since
`A` and
`B` are independent, we have
`\mathbb P(A\cap B)=\mathbb P(A)\cdot\mathbb P(B)`. So


`\mathbb P(A\cup B)=0.2+0.4-0.2\cdot0.4=0.52`