Question

Of all those people who enter Uncle`s Stereo, a discount electronics store in New York City, 28% purchase a digital camera, 5% buy a home theater receiver, and 4% buy both. Suppose a customer is selected at random. What is the probability that the customer buys either a digital camera or a home theater receiver but not both

Answer 1

25% of the people either buys a digital camera or a home theater receiver buth not both.

Explanation:

The percentage of the customers that buy both a digital camera (D) and a home theather receiver (H) are included in the respective percentages (28% and 5%), so to calculate the percentage that buy only one of the items, we have to substract the percentage that buy both items from each of the percentages:

- If 28% of the people purchase a digital camera, and 4% buy both items, then 28-4=24% of the people buy only a digital camera.

- If 5% of the people purchase a home theater receiver, and 4% buy both items, then 5-4=1% of the people buy only a home theater receiver.

Then, we can add 24% and 1% and have that 25% of the people either buys a digital camera or a home theater receiver buth not both.