In a game, the entry fee is of Rs.5. The game consists of a tossing a coin 3 times. If one or two heads show, Sweta gets her entry fee back. If she throws 3 heads, she receives double the entry fees. Otherwise she will lose. For tossing a coin three times, find the probability that she

(i) loses the entry fee.


(ii) gets double entry fee.


(iii) just gets her entry fee.

Total possible outcomes of tossing a coin 3 times,

S = {(HHH),(TTT),(HTT),(THT),(TTH),(THH),(HTH),(HHT)}


∴ n(S) = 8


(i) Let E1 = Event that Sweta losses the entry fee


= She tosses tail on three times


n(E1) = {(T T T)}



(ii) Let Event that Sweta gets double entry fee


= She tosses tail on three times = {(HHH)}


n(E2) = 1



(iii) Let Event that Sweta gets her entry fee back


= Sweta gets heads one or two times


= {(HTT),(THT),(TTH),(HHT),(HTH),(THH)}


n(E3) = 6



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