math

in a shipment of 20 computers, 3 are defective

three computers are randomly selected and tested. what is the probability that all 3 are defective if the first and second ones are not replaced after being tested.

a. 1/760
b.1/1140
c.27/8000
d.3/5000

i chose D, is this correct

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  1. First one 3/20
    Second one 2/19
    third one 1/18
    3/20*2/19*1/18 = 1/(3*20*19) =1/1140

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  2. The answer is B Explanation: 3/20*2/19*1/18=1/(3*20*19)=1/1140

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  3. yffffff'

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