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प्रश्न
Let X ~ B(10, 0.2). Find P(X = 1).
उत्तर
X ~ B(10, 0.2)
∴ n = 10, p = 0.2
∴ q = 1 - p = 1 - 0.2 = 0.8
The p,m.f. of X is given by
P(X = x) = `"^nC_x p^x q^(n - x)`
∴ P(X = x) = `"^10C_x (0.2)^x xx (0.8)^(10 - x)`, ...[x = 0, 1, 2, 3,....,10]
P(X = 1) = `"^10C_1 (0.2)^1xx(0.8)^(10 - 1)`
P(X = 1) = 10 × (0.2) × (0.8)9
P(X = 1) = 2 (0.8)9
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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`
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= `square` + `square`
= `2/27`
