Question

If the rainy today 0.7. Find the probability of getting not rainy today​

Answer 1

Answer:

Alright, so let T := it will rain today and M := it will rain tomorrow.

P(T) = 0.4

P(M) = 0.3

P(MT) = P(M|T)P(T) = P(T|M)P(M) = 0.12

Thus, we can see that

P(M|T) = 0.3 = P(M)

And

P(T|M) = 0.4 = P(T)

Hence, we can tell that whether it rains today is independent of whether it rains tomorrow (this was actually a more interesting question before you changed P(MT) to 0.12, because P(MT) = 0.2 implies that these events are not independent).

Since they are independent, we can calculate the probability that we will get rain one day or the other but not both pretty easily. It is just:

(1-P(T))P(M) + (1-P(M))P(T)

Or

0.6*0.3 + 0.7*0.4

Which is 0.46

it is not your answer but similar

Answer 2

Answer:

Rainy today (0.7)+Not rainy today =1

So not rainy today =0.3