# Ex 13.5, 4 - Chapter 13 Class 12 Probability

Last updated at May 29, 2018 by Teachoo

Last updated at May 29, 2018 by Teachoo

Transcript

Ex 13.5, 4 Five cards are drawn successively with replacement from a well-shuffled deck of 52 cards. What is the probability that (i) all the five cards are spades? (ii) only 3 cards are spades? (iii) none is a spade? Let X : be the number of spade cards Drawing is a Bernoulli trial So, X has binomial distribution P(X = x) = nCx 𝒒𝒏−𝒙 𝒑𝒙 n = number of cards drawn = 5 p = Probability of getting spade card = 1352= 14 q = 1 – p = 1 – 14= 34 Hence, P(X = x) = 5Cx 𝟑𝟒𝟓−𝒙 𝟏𝟒𝒙 • P(all cards are spade) = 5𝐶5 145 340 = 145 = 𝟏𝟏𝟎𝟐𝟒 • P(only three cards are spade) = 5𝐶3 143 342 = 5!3! 2! × 91024 = 𝟒𝟓𝟓𝟏𝟐 (iii) P(none of them are spade) = 5𝐶0 140 345 = 345 = 𝟐𝟒𝟑𝟏𝟎𝟐𝟒

Chapter 13 Class 12 Probability

Serial order wise

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