Question

The probability that it'll rain tomorrow in Ohio is 30%

Answer 1

It raining in Alaska and raining in Ohio are independent events. One does not control the other or affect the other in any way.

For two independent events (let's call them A and B), the Probability of A and B both occurring is given by P(A and B) = P(B) x P(B).

For this problem, let A = rain in Ohio and B= rain in Alaska.

P(A and B) = P(A) x P(B)
$\frac{12}{100} =(P(A))( \frac{3}{10} )$
$( \frac{12}{100}) ( \frac{100}{30} )=P(A)$
$P(A)= \frac{12}{30}= \frac{2}{5}$