Question

The probability that it will rain today is 0.4, and the 

probability that it will rain tomorrow is 0.3. The 
probability that it will rain both days is 0.2. 
Determine the probability that it will rain today or 
tomorrow

Answer 1

Prob. it will rain today or tomorrow = 0.4+0.3 = 0.7
or means +
and means x