4. (4P) In an urn are 3 blue and 5 red balls.
(a) Consider drawing with removing of 2 balls. What is the probability
that
i. only red balls are drawn?
ii. exactly one blue and one red ball is drawn?
(b) Consider drawing with removing of 3 balls. What is the probability
that only balls of one color are drawn?
Justify your answers, do not just give the result.