Three coins are tossed once. Find the probability of getting
(i) 3 heads (ii) 2 heads (iii) at least 2 heads
(iv) at most 2 heads (v) no head (vi) 3 tails
(vii) exactly two tails (viii) no tail (ix) at most two tails.
When three coins are tossed once, the sample space is given by
S = {HHH, HHT, HTH, THH, HTT, THT, TTH, TTT}
∴Accordingly, n(S) = 8
It is known that the probability of an event A is given by
(i) Let B be the event of the occurrence of 3 heads. Accordingly, B = {HHH}
∴P(B) =
(ii) Let C be the event of the occurrence of 2 heads. Accordingly, C = {HHT, HTH, THH}
∴P(C) =
(iii) Let D be the event of the occurrence of at least 2 heads.
Accordingly, D = {HHH, HHT, HTH, THH}
∴P(D) =
(iv) Let E be the event of the occurrence of at most 2 heads.
Accordingly, E = {HHT, HTH, THH, HTT, THT, TTH, TTT}
∴P(E) =
(v) Let F be the event of the occurrence of no head.
Accordingly, F = {TTT}
∴P(F) =
(vi) Let G be the event of the occurrence of 3 tails.
Accordingly, G = {TTT}
∴P(G) =
(vii) Let H be the event of the occurrence of exactly 2 tails.
Accordingly, H = {HTT, THT, TTH}
∴P(H) =
(viii) Let I be the event of the occurrence of no tail.
Accordingly, I = {HHH}
∴P(I) =
(ix) Let J be the event of the occurrence of at most 2 tails.
Accordingly, I = {HHH, HHT, HTH, THH, HTT, THT, TTH}
∴P(J) =