Karen Thorpe is a purchasing agent for GymNast, Inc., a manufacturer of sports equipment. Karen has authority to sign checks in payment for purchases made by GymNast. Karen makes out three checks to suppliers and signs each one differently, as follows:
1. GymNast, Inc., by Karen Thorpe, purchasing agent.
2. Karen Thorpe, purchasing agent.
3. Karen Thorpe.
Discuss whether Karen is personally liable on each signature and whether the principal, GymNast, Inc., can be held liable.