Question

A weather station in a major city in the Northwest kept data about the weather conditions over the past year. The probabilities are displayed in the table below:
Hot Mild Cold
Sunny 0.15 0.30 0.10
Cloudy 0.10 0.25 0.10


If a random day is chosen from this data, what is the probability that the day was hot or sunny?

Answer 1

0.15 + 0.1 + 0.3 + 0.1 = 0.65

Answer 2

It is important to note that all the information's required are already given in the question

Probability that a day will be hot = 0.15 + 0.10
                                                   = 0.25
Probability that a day will be sunny = 0.15 + 0.30 + 0.10
                                                        = 0.55
Adding the above two probabilities, we get = 0.25 + 0.55
                                                                     = 0.80
Now
Probability that a day will be both hot and sunny = 0.15
So
Probability that a day was hot or sunny = 0.80 - 0.15
                                                               = 0.65
I hope the procedure is clear enough for you to understand.