Question 1122242:  at a shopping mall, 40% of the shoppers are willing to take a survey. estimate the probability that out of the next 5 random shoppers, there will be 3 or more in a row willing to take the survey? 
 Answer by Boreal(15235)      (Show Source): 
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Each one has two possibilities, so there are 32 choices in all, 2^5. 
for three of these, the probability is 3*0.4^3*0.6^2=0.0691 
for four of these, the probability is 4*0.4^4*0.6=0.0614 
for five of these, the probability is 0.4^5=0.0102 
The sum is 0.1407 ANSWER 
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