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Question 3. Suppose an alien species has 3 blood types U, X and Z, blood transfer safety chart is as follows: From type To type Chance of compatibility U X 50% U Z 100% X U 0% X Z 70% Z U 100% Z X 50% Blood transfers between the same blood types are always 100% safe. Suppose in a local Village the population is distributed as follows Blood type U X Z Population proportion 45% 35% 20% Two aliens A and B are close friends. What is the probability of blood transfer compatibility if A donates to B? (a). Answer this question if they don't know their own blood types. Assume they are independently sampled from the population. (b). Answer this question if A's blood type is known to be U, but B's remains unknown. Suppose B is randomly sampled from the population