document.write( "Question 328413: Spacecraft are expected to land in a prescribed recovery zone 80% of the time. Over a period of time,six spacecraft land.
\n" ); document.write( "a)Find the probability that none lands in the prescribed zone.
\n" ); document.write( "b)Find the probability that at least one will land in the prescribed zone.
\n" ); document.write( "c)The landing program is called successful if the probability is 0.9 or more that three or more out of six spacecraft will land in the prescribed zone. Is the program successful?
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Algebra.Com's Answer #235274 by Fombitz(32388)\"\" \"About 
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a) P(none)=\"%280.2%29%5E6=0.000064\"
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\n" ); document.write( "b)At least one means \"not none\".
\n" ); document.write( "P(not none)+P(none)=\"1\"
\n" ); document.write( "P(not none)=1-P(none)=\"1-0.000064=0.999936\"
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\n" ); document.write( "c) Find P(3 or greater successes)=\"P%283%29%2BP%284%29%2BP%285%29%2BP%286%29\"
\n" ); document.write( "\"P%280%29=1%2A%280.8%29%5E0%2A%280.2%29%5E6=0.000064\"
\n" ); document.write( "\"P%281%29=6%2A%280.8%29%5E1%2A%280.2%29%5E5=0.001536\"
\n" ); document.write( "\"P%282%29=15%2A%280.8%29%5E2%2A%280.2%29%5E4=0.01536\"
\n" ); document.write( "\"P%283%29=20%2A%280.8%29%5E3%2A%280.2%29%5E3=0.08192\"
\n" ); document.write( "\"P%284%29=15%2A%280.8%29%5E4%2A%280.2%29%5E2=0.24576\"
\n" ); document.write( "\"P%285%29=6%2A%280.8%29%5E5%2A%280.2%29%5E1=0.39322\"
\n" ); document.write( "\"P%286%29=1%2A%280.8%29%5E6%2A%280.2%29%5E0=0.26214\"
\n" ); document.write( "P(>=3)=\"P%283%29%2BP%284%29%2BP%285%29%2BP%286%29\"
\n" ); document.write( "P(>=3)=\"0.08192%2B0.24576%2B0.39322%2B0.26214=highlight%280.983%29\"
\n" ); document.write( "Since \"P%3E0.9\", success.
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\n" ); document.write( "We could have also calculated,
\n" ); document.write( "\"P%280%29%2BP%281%29%2BP%282%29=0.000064%2B0.001536%2B0.01536=0.01696\"
\n" ); document.write( "and subtracted from 1
\n" ); document.write( "\"P=1-P%280%29-P%281%29-P%282%29=1-0.01696=0.983\"
\n" ); document.write( "Same answer but saving one step.
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