SOLUTION: Please help me to explain how to solve this problem..thanks 3 electric lamps are to be fitted in a room. 3 bulbs are chosen at random from 10 bulbs out of which 6 work. What is

Question 74040: Please help me to explain how to solve this problem..thanks
3 electric lamps are to be fitted in a room. 3 bulbs are chosen at random from 10 bulbs out of which 6 work. What is the chance the room will be lighted?
this was a problem on a worksheet.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
3 electric lamps are to be fitted in a room. 3 bulbs are chosen at random from 10 bulbs out of which 6 work. What is the chance the room will be lighted?
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I assume the room will be lighted if at least one of the 3 bulbs selected
is not defective.
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There are 4C3= 4 groups of bulbs that are all defective
There are 10C3 = 120 total number of groups of 3.
--------------
The probability of selecting a group that has at least
one non-defective bulb is 116/120 = 0.966666...
============
Cheers,
Stan H.
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