there were two defective USB thumb drives and a shipment of 500 how many drives can be expected to be defective in a shipment of 20,000

Answer: 80

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Explanation:

x = number of defective drives in the shipment of 20,000 total

We are told that 2 defective drives are in the shipment of 500. So the first fraction to set up is 2/500

The second fraction is x/20000 as we divide in the same order as before (number of defective over the total)

Set those two fractions together to get this proportion
2/500 = x/20000

Now cross multiply
2/500 = x/20000
2*20000 = 500*x
40000 = 500*x
500x = 40000

The last step is to divide both sides by 500 to isolate x
500x = 40000
500x/500 = 40000/500
x = 80 which is the answer we want

Note: This is an expected/estimated amount and not entirely guaranteed to be reality. It's based on the previous ratio of 2/500, assuming the same ratio is held in check.