The waiter at an expensive restaurant has noticed that 60% of the couples order dessert and coffee. However, 20% of the couples who order dessert don't order coffee. What is the probability that the next couple the waiter seats will not order dessert?
I solved this pretty fast this way:
60% dessert and coffee
--> 40% nothing, dessert, or coffee
Let them be the same probability --> 40% / 3 = 13,333%
40% - 13% = 27% --> Answer has to be around this range --> B is closest