Four pairs of lords and ladies all went to a royal ball. Each lord was wearing one color (yellow, red, blue, or green) and each lady was also wearing one of these colors. No couple was wearing the same color, so it was hard to tell who was married to who.

Using the clues, can you determine which lord is with which lady?

1. The Green Lord is with the Red Lady, if and only if the Yellow Lord is with the Blue Lady.

2. The Yellow Lord is with the Red Lady if and only if the Green Lord is with the Yellow Lady

3. The Red Lord is with the Blue Lady, if and only if the Green Lord is with the Red Lady.

I used a table to figure this one out.

Since the Green Lord is with the Red Lady if and only if the Yellow Lord is with the Blue Lady and the Green Lord is also with the Red Lady if and only if the Red Lord is with the Blue Lady I concluded that the Green Lord could not be with the Red Lady, and neither the Yellow Lord nor the Red Lord could be with the Blue Lady.  As no couple wore the same color this left only the Green Lord for the Blue Lady. 

Since the Green Lord was already with the Blue Lady, I concluded that he could not be with the Yellow Lady, and thus the Yellow Lord was not with the Red Lady.  This left only the Blue Lord for the Red Lady. 

As the Yellow Lord could not be with the Yellow Lady, I concluded that the Yellow Lord was with the Green Lady and the Red Lord was with the Yellow Lady.

In a nut shell:

Green Lord with Blue Lady
Blue Lord with Red Lady
Yellow Lord with Green Lady
Red Lord with Yellow Lady

 

Posted by Grace on 2004-05-12 14:53:34