Asked by bernie

twenty light bulbs are tested three light bulbs fail the test. two light bulbs are selected at random without replacement from this collection of bulbs find the probablilty that both light bulbs failed the test. round the answer 3 decimals places
Answered by Scott
the failure rate is 15%

the probability of both bulbs being bad is ... .15 * .15
Answered by Reiny
it said "without replacement" , so the prob that the second is faulty is not 15%

Bernie, what part of my solution did you not like ?
http://www.jiskha.com/display.cgi?id=1469831346