Since there are 3 sculptors and 5 photographers, and the question is asking for either a sculptor or photographer, you add them together. There are a total of 18 artists, and the probability is the chance of a certain thing happening over the total amount of things that can happen (i.e. a coin landing on heads is 50%).
I could be wrong, but probably not. It was hard to figure out what the plot numbers were and the answer choices because the picture was super blurry. That's why I said I might be wrong.
