Answer» When three coins are tossed, the sample space is given by S = {HHH, HHT, HTH, HTT, THH, THT, TTH, TTT} (i) Two events that are mutually exclusive can be A: getting no heads and B: getting no tails This is because sets A = {TTT} and B = {HHH} are disjoint. (ii) Three events that are mutually exclusive and exhaustive can be A: getting no heads B: getting exactly one head C: getting at least two heads i.e., A = {TTT} B = {HTT, THT, TTH} C = {HHH, HHT, HTH, THH} This is because A ∩ B = B ∩ C = C ∩ A = Φ and A U B U C = S (iii) Two events that are not mutually exclusive can be A: getting three heads B: getting at least 2 heads i.e., A = {HHH} B = {HHH, HHT, HTH, THH} This is because A ∩ B = {HHH} ≠ Φ (iv) Two events which are mutually exclusive but not exhaustive can be A: getting exactly one head B: getting exactly one tail That is A = {HTT, THT, TTH} B = {HHT, HTH, THH} It is because, A ∩ B =Φ, but A B ≠ S (v) Three events that are mutually exclusive but not exhaustive can be A: getting exactly three heads B: getting one head and two tails C: getting one tail and two heads i.e., A = {HHH} B = {HTT, THT, TTH} C = {HHT, HTH, THH} This is because A ∩ B = B ∩ C = C ∩ A = Φ, but A U B U C ≠ S
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