Answer:
The dentist should get a new drill and it does not matter who pays for the new drill
Step-by-step explanation:
Based on the information given the economically efficient outcome is that The dentist should get a new drill and it does not matter who pays for the new drill reason been that the building is been share by both the dentist and the radio station in which the electrical current from the dentist's drill was the one who causes static in the radio broadcast making them to lose some amount of money which means the dentist should go ahead and buy a new drill in which it does not matter who pays for the drill because they both shared the building .