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Three coins are tossed simultaneously : P is the event of getting at least two heads. Q is the event of getting no head. R is the event of getting head on second coin.

(i) Three coins are tossed simultaneously :
P is the event of getting at least two heads.
Q is the event of getting no head.
R is the event of getting head on second coin.

Sol. When three coins are tossed
S = { HHH, HTH, THH, TTH, HHT, HTT, THT, TTT }
∴  n (S) = 8
P is the event of getting atleast two head
P = { HHH, HTH, THH, HHT }
∴  n (P) = 4
Q is the event of getting no head
Q = { TTT }
∴  n (Q) = 1
R is the event of getting head on second coin
R = { HHH, THH, HHT, THT }
∴  n (R) = 4
Here, P∩Q = ϕ
P and Q are mutually exclusive events.
Here, Q∩R = ϕ

Q and R are mutually exclusive events.