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Ten percent of screws produced in a certain factory turn out to be defective. Find the probability that in a sample of 10 screws chosen at random, exactly two will be defective.
a) 0.2

b) 0.25

c) 0.8
d) 0.3 79.
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We can apply here BINOMIAL DISTRIBUTION,

Prob [defective] = 0.1

Prob [non defective] = 0.9

n = 10

r = 2 {exactly 2}

Binomial Distribution :-

nCr * (p)^r * (q)^(n-r)

10C2 * 0.1^2 * 0.9^8

0.1937102445 

or

0.2 

Hence a) 0.2 is correct answer.

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