SOLUTION: three plants manufacture light bulb. plant 1 manufactures 40% of the light bulbs, plant 2 manufactures 35% of the light bulbs and plant 3 manufactures 25% of the light bulbs. at

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Question 691001: three plants manufacture light bulb. plant 1 manufactures 40% of the light bulbs, plant 2 manufactures 35% of the light bulbs and plant 3 manufactures 25% of the light bulbs. at plant 1, 10 out of every 100 bulbs is defective, plant 2, 13 out of every 100 bulbs is defective, plant 3, 20 out of every 100 bulbs is defective. what is the probability that a costumer that purchases a bulb from dims factory buys one defective?
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
We could start based on a total of x bulbs manufactured,
but we can calculate based on any total number of bulbs manufactured,
and the ratios would be the same anyway.
(I will choose 2000 because that gives me nice round numbers).

For every 2000 bulbs manufactured, the following is true:
Plant #1 makes 0.40%2A2000=800 bulbs (40% of 2000), including
%2810%2F100%29%2A800=80 defective bulbs.
Plant #2 makes 0.35%2A2000=700 bulbs (35% of 2000), including
%2813%2F100%29%2A700=101 defective bulbs.
Plant #3 makes 0.25%2A2000=500 bulbs (25% of 2000), including
%2820%2F100%29%2A500=100 defective bulbs.

Out of a total of 2000 bulbs, 80%2B101%2B100=281 bulbs are defective.
A customer who buys one bulb from that company has a
281%2F2000 (or 14.05%) probability of getting a defective bulb.