Henry just landed three dates with a really hot girl (I know it usually doesn't work that way in the real world but this is GMAT world!). The probability that he will get her to (I know what you're thinking but no!)...see his apartment on date # 1 is 50%. The probability that she'll see his apartment on day 2 is 50%. The probability she'll come over on day 3 is also 50%. What is the probability that she'll visit Henry's apartment on at least one of the dates?
talk about feeling lonely
prob that she does not visit at all 0.5 * 0.5 * 0.5 = 0.125
prob that she visits atleast one = 1 - 0.125 = 0.875