math challenge

Week of July 8 - 14, 1996

Which Pig is Which?

Three piglets were left at home while their mother Mrs. Pig went to market. There were two older girls named Porcina and Swindia, and a baby piglet Hogan. Porcina always tells the truth. Swindia always lies. Hogan is too young to talk, but is adept at destruction. Their mother, Mrs. Pig, arrived home and surveyed a scene of chaotic destruction. "WHO DID THIS?!" she squealed.

The older girl-pig said, "We all did it."
The younger girl-pig (the middle sibling) said, "He helped do it," pointing to Hogan.

What are the names of the older sister and the younger sister?

See the solutions