Question 782759
3.	A salesman has a 60% chance of making a sale to any one customer. The behaviour of successive customers is independent. If two customers A and B enter, what is the probability that the salesman will make a sale to A or B.
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.6*.6=.36 probability the salesman will make a sale to both of them. .6-.36=0.24 the probability he will make a sale to only the first one of them he meets.  .24 the probability he makes a sale only the second one he meets.
.36+.24+.24=0.84 the probability that the salesman will make a sale to A or B. 
Drawing an Venn diagram of the situation will clarify things.
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Ed