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Question
Determine P(E|F).
Two coins are tossed once, where
E: tail appears on one coin, F: one coin shows head
Solution
S = {HH, TH, HT, TT}
n(S) = 4
E : A coin shows tails,
E = {TH, HT}
P(E) = `1/2`
F: Head appears on a coin,
F = {TH, HT}
P(F) = `1/2`
E ∩ F = {TH, HT}
n(E ∩ F) = 2
P(E ∩ F) = `2/4 = 1/2`
Thus, P(E | F) = `(P(E ∩ F))/(P(F))`
`= (1/2)/(1/2)`
= 1
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