SOLUTION: A quality control inspector examined 200 light bulbs and found 18 defective.At this rate,how many defective bulbs would there be in a lot 22000 bulbs?

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Question 542354: A quality control inspector examined 200 light bulbs and found 18 defective.At this rate,how many defective bulbs would there be in a lot 22000 bulbs?
Answer by neatmath(302) About Me  (Show Source):
You can put this solution on YOUR website!

You can set up a proportion to solve this problem:

18 is to 200 as x is to 22000?

18%2F200=x%2F22000

Then cross multiply to solve:

22000%2A18=200%2Ax

396000=200x

x=1980

So we would "expect" to find 1980 defective lightbulbs in a lot of 22000 bulbs.

If this type of problem interests you,

there is a whole field of study about this type of situation called Statistical Quality Control.

I hope this helps!