Four stamp dealers (Abby, Baker, Carmen, and David) each attend a different day of a stamp convention, held Thursday through Sunday of one week.
Carmen attends earlier
David attends later than Baker.
You may wish to draw a simple diagram symbolizing the information contained in the conditions. Since you know that Carmen attends earlier than Abby, you might wish to put Carmen somewhere to the left of Abby. (Note that “earlier” does not mean exactly one day earlier, but rather “sometime earlier”):
And since David attends later than Baker:
Notice that while no exact days can be determined from the information, you do know that C must be somewhere to the left of A and that B must be somewhere to the left of D. you can, if you wish, eliminate some possibilities as impossible, or “rule breakers”: