suppose that an experiment has four possible outcomes. a,b,c and d. if p(a)= p(b)= p(c) and p(d)= 2p(a) what is the probabilty of each event

Answer 1

If p(a)= p(b)= p(c) and p(d)= 2p(a), then
5p(a) = 1.

You should be able to take it from there.