Determine whether the following ads have valid or invalid co

Determine whether the following ads have valid or invalid conclusions based on each of the first statements. People who use Bakerite ovens get satisfactory baking results. If you don\'t get satisfactory baking results, then you are not using a Bakerite oven. If you have your car rustproofed by Bob\'s Garage, you will avoid rust problems. Therefore, if you do not have your car rustproofed by Bob\'s Garage, you will not avoid rust problems.

Solution

Invalid conclusion as it is not necessary that if you dont go to Bob\'s garafe your car will necessarily have rust problem .