Question 143938
The administrator samples 12 of the PCs connected to the LAN, and finds that 7 are infected; use proportion to estimate the number of infected PCs if there are a total of 117 PCs connected to the LAN.
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x/117 = 7/12
x = 117(7/12) 
x = 68.25
Rounding down you get x = 68 of the 117 are infected.
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Cheers,
Stan H.