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प्रश्न
Two different coins are tossed simultaneously. What is the probability of getting:
- at least one head?
- at most one tail?
- a head and a tail?
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उत्तर
A coin has two faces Head and Tail.
∴ Two coins are tossed, which are HH, HT, TH, and TT.
S = {(H, H), (H, T), (T, H), (T, T)}
∴ n(S) = 4
(i) A is an event (getting at least one head)
∴ A = {(H, T), (T, H), (H, H)} or n(A) = 3
Thus, the probability of getting at least one head
= `(n(A))/(n(S))`
= `3/4`
(ii) Now, Outcomes with at most with 1 tail = HH, HT, TH
Thus, P(getting at most 1 tail) = `"Number of outcomes with almost 1 tail"/"Total number of outcomes"`
= `3/4`
(iii) Let A be the event of getting one head and one tail, and let B be the event of getting at most two tails.
A = {HT, TH}
n(A) = 2
B = {HH, HT, TH, TT}
n(B) = 4
P(getting one head and one tail):
= P(A) = `(n(A))/(n(S))`
= `2/4`
= `1/2`
