Question

The probability that it will rain tomorrow is 0.85. What is the probability that it will not rain tomorrow?

Answer 1

$$\begin{gathered} \mathrm{Let}\mathrm{A}\mathrm{be}\mathrm{the}\mathrm{event}\mathrm{of}\mathrm{raining}\mathrm{tomorrow}. \\ \mathrm{The}\mathrm{probability}\mathrm{that}\mathrm{it}\mathrm{will}\mathrm{rain}\mathrm{tomorrow},\mathrm{P}\left(\mathrm{A}\right),\mathrm{is}0.85. \\ \mathrm{Since}\mathrm{the}\mathrm{event}\mathrm{of}\mathrm{raining}\mathrm{tomorrow}\mathrm{and}\mathrm{not}\mathrm{raining}\mathrm{tomorrow}\mathrm{are}\mathrm{complementary}\mathrm{to}\mathrm{each}\mathrm{other},\mathrm{the}\mathrm{probability}\mathrm{of}\mathrm{not}\mathrm{raining}\mathrm{tomorrow}\mathrm{is}: \\ \mathrm{P}\left(\overline{\mathrm{A}}\right)=1-\mathrm{P}\left(\mathrm{A}\right)=1-0.85=0.15 \end{gathered}$$