Hi. Can someone help me out. i'm looking a how a problem was solved and can't figure out why (or how) the solution got from point a--b

basically, it states 1- p(C' ^ T') = p(C v T)

this may be basic logic in probability but i'm lost... how does the probability of C' and T' equal the probabilty of C or T?

the next step just uses the general addition rule: p(C v T) = p(C) + p(T) - p(C ^ T) which i understand completely, just having trouble w/ the first part. can someone help me out please and what rule is that???