Question

Given two independent events:
P(A) = 2/9
P(B) = 4/11
Can you check if the answers are correct.
(a)
P(A and B) (the answer is 8/99)
(b)
P(not A and not B) (the answer is 91/99)
(c)
P(at least one event happens) (the answer is 48/99)

Answer 1

These all seem good! When finding the probability of both happening you multiplied (a), when finding the probability of neither you subtracted 8 from the total chances to give you it (b), and lastly you added the two probabilities to give you (c).

Answer 2

Thanks!

Answer 3

I think the last one is incorrect.

Answer 4

C.
\[P(does nothappen)=P(notA)P(notB)=\frac{ 7 }{ 9 }\times \frac{ 7 }{ 11 }=\frac{ 49 }{ 99}\]
\[P(at~least~one~event~happens)=1-\frac{ 49 }{ 99 }=?\]
i may be incorrect.

Answer 5

Thanks! It means (b) is incorrect as well?

Answer 6

i think so.

Answer 7

So
(a) is correct: 8/99
(b) should be 49/99
(c) should be 50/99

Answer 8

yes

Answer 9

Thanks!

Answer 10

yw