A electrical goods retail warehouse concludes from a customer survey that 40% of customers who seek advice from the sales staff buy an appliance and that 20% of those entering the warehouse who do not seek such advice buy an appliance. If 30% of all customers entering the warehouse seek advice, what is the probability that a customer entering the warehouse buys an appliance.?

Let denote the number of customers.

The number of customers that seek advice is .

The number of customers that do not seek advice is thusly

40% of the customers that do seek advice buy a device, denoted with that is 12% of the total customers here buy a device.

20% of the customers that do not seek advice buy a device, denoted with so 14% of the total customers here buy a device.

Together, the percentage of customers that will buy an applicance on the end of the day is .

So the probability from that follows that when a customer enters the shop there exists a 26% probability that the customer will end up buying a device.

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