Answer :
Let S be the sample space.
S = {HHH, HHT, HTH, THH, HTT, THT, TTH, TTT}
(i) Let A be the event of getting 3 heads
A = {HHH}
Required probability = P(A)
= 
= 
(ii) Let A be the event of getting 2 heads
A = {HHT, HTH, THH}
No. of favourable outcomes = 3
P(A) = 
(iii) Let A be the event of getting alteast 2 heads
A = {HHH, HHT, HTH, THH}
No. of favourable outcomes = 4
P(A) = 
= 
(iv) Let A be the event of getting at most 2 heads.
A = {HHT, HTH, THH, HTT, THT, TTH, TTT}
No. of favourable outcomes = 7
Probability (at most 2 heads) = 
(v) Let A be the event of getting no head
A = {TTT}
No. of favourable outcome = 1
Probability (three tails) = 
(vi) Let A be the event of getting 3 tails
A = {TTT}
No. of favourable outcome = 1
Probability (three tails) = 
(vii) Let A be the event of getting exactly two tails
A = {HTT, THT, TTH}
No. of favourable outcomes = 3
Probability(exactly two tails) =
(viii) Let A be the event of getting no tail
A = {HHH}
No. of favourable outcome = 1
Probability (no tail) =
(ix) Let A be the event of getting at most two tails
A = {HHT, HTH, THH, HTT, THT, TTH, HHH}
No. of favourable outcomes = 7
Probability (at most two tails) = 
.
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