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Probability

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Probability

by naaga » Thu Mar 05, 2009 4:08 am
On saturday morning Malachi will begin a camping vacation and he will return home at the end of the first day on which it rains. If on the first three days of the vacation the probability of rain on each day is 0.2, what is the probability that Malachi will return home at the end of the day on the following Monday ?

0.008
0.128
0.488
0.512
0.640

friends anyone can explain clearly, thanks in advance.
Last edited by naaga on Thu Mar 05, 2009 5:22 am, edited 1 time in total.
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by scoobydooby » Thu Mar 05, 2009 5:22 am
probability of rain=0.2 so probability of no rain=0.8 (mutually exclusive events)

if M returns end of Monday, then Monday must be the first day it rained
so sat (no rain), sun(no rain), mon(rain)

or probability of M returning home on Monday night given that it rains only on monday and not on saturday and sunday
=0.8*0.8*0.2
=0.128
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