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प्रश्न
Choose the correct option from the given alternatives:
The probability of a shooter hitting a target is `3/4` How many minimum numbers of times must he fire so that the probability of hitting the target at least once is more than 0·99?
विकल्प
2
3
4
5
उत्तर
4
Hint:
P(X ≥ 1) > 0.99
∴ 1 - P(X = 0) > 0.99
∴ P(X = 0) < 0.01 = `1/100`
∴ `"^nC_0 (3/4)^0 (1/4)^n < 1/100`
∴ `(1/4)^n < 1/100`
∴ n = 4
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Solution:
A pair of dice is thrown 3 times.
∴ n = 3
Let x = number of success (doublets)
p = probability of success (doublets)
∴ p = `square`, q = `square`
∴ x ∼ B (n, p)
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= `square` + `square`
= `2/27`
