For instance, his friend Jon can only come if he brings something like orange juice. Stacy can only come if she takes bags of peanut M&M's and such. Billy could go if he takes denim jeans, but he must also bring bananas. However, Eric's friend Janet couldn't go on vacation with him no matter what she brings.
Eric's friend Russel could go with him if he brings ketchup. If Elvis were alive, though, he couldn't go with Eric.
Eric's friend Ashley has the same requirements Stacy has, and so does his other friend, Yao. However, Yao has an additional requirement: He must also bring ripe pumpkins, which Stacy and Ashley need not bring.
Eric's friend Paul could go if he brings plums, and Garry could go if he brings some $20 bills, but he must also bring tomatoes and a yellow smiley face. Eric himself is only able to go on vacation because he is bringing his wife, who had just returned from Florida.
So the question is: Can Robby go on vacation? If he can't, why not? If he can, what must he bring?