Master gmat 2010 part 37

Example (Argument 4) Premise: All red gremlins are spotted. Premise: All spotted gremlins are female. (Assumption: A gremlin must be either male or female but not both.) Valid inference: All red gremlins are female. Valid inference: No male gremlin is red. Invalid inference: No gremlin that is not red is female. Invalid inference: All female gremlins are red. In arguments 1–4, each statement is essentially an all-or-none assertion (signaled by words such as “all” and “no”). In this next series of arguments, the word “some” is introduced into a premise. For each form, try conjuring up your own example...