a. Suppose first that it has been documented that, all else being equal, illegal substances are more likely to be transported in pick-up trucks than in passenger cars. Put differently, if pick-up truck owners are searched with the same probability as passenger car owners, law enforcement officials will be more likely to find illegal substances when they randomly search a pick-up truck than when they randomly search a passenger vehicle. If the objective by police is to find the most illegal substances given that they have limited resources (and thus cannot search everyone), is it optimal for them to search randomly?