Question

If the probability that it may rain tomorrow is 2/5, what is the probability that it may not rain?

Answer 1

Let $A-$ the event that it may rain tomorrow, in that case $\bar{A}-$ the event that it may not rain tomorrow.

$P(A)=\cfrac{2}{5};\\ P(\bar{A})=1-P(A)=1-\cfrac{2}{5}=\cfrac{3}{5}.$