Question

if a box contains 10 left handed and 20 right handed screws what is the probability of obtaining at least 1 right handed screws in drawing 2 scews with replacement

Answer 1

Answer:

If a box contains 10 left handed and 20 right handed screws what is the probability of obtaining at least one right handed screw in drawing 2 screws with replacement?

P(at least 1 right) = 1 - P(2 left) = 1 - (1/3)^2 = 8/9

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Will the probability in the answer in the first question increase or decrease if we draw without replacement.

Ans: increase

1 - (10/30)(9/29) = 0.8966